1977 Mercury Comet Catalytic Converters

Keep Your 1977 Mercury Comet in Top Shape with Quality Catalytic Converters

Whether you’re repairing or upgrading your Catalytic Converter, using high-quality parts is key to keeping your 1977 Mercury Comet looking sharp and performing at its best. At Advance Auto Parts we carry a wide selection of dependable options, including Catalytic Converters. Whether you’re replacing a damaged part or enhancing your truck’s style and protection, you’ll find exactly what you need to get the job done right.

Top-Rated Catalytic Converters from Trusted Brands

Looking for a reliable Catalytic Converter? We’ve got you covered with options from brands you know and trust like Walker. For example, Walker Catalytic Converters start at just $131.99 with an average 4.2 star rating. With over 8 reviews and a solid 4 star average, you can shop with confidence knowing other Mercury Comet owners approve.

Competitive Prices and Extensive Inventory

The average price for a 1977 Mercury Comet Catalytic Converter at Advance Auto Parts is around $293.11, with a range that starts at $83.99 and goes up to $560.99. With 6 options in stock from 2 trusted brands, finding the right fit is easy. Popular picks like Standard EPA Universal Catalytic Converter – 2" Inlet (ID) 2" Outlet (ID), CalCat CARB Universal Catalytic Converter – 2" Inlet (ID) 2" Outlet (ID), and CalCat CARB Universal Catalytic Converter start at just $83.99 and offer a great balance of form and function.

Explore Related Parts

While you’re upgrading or replacing your Catalytic Converter, don’t forget to check out other key components like Exhaust Pipes and Exhaust Tips. At Advance Auto Parts, we’re here to help you keep your 1977 Mercury Comet in peak condition, inside and out.

Essential 1977 Mercury Comet Catalytic Converters

Walker – Standard EPA Universal Catalytic Converter – 2" Inlet (ID) 2" Outlet (ID) (Part No.15036)

Standard EPA Universal Catalytic Converter - 2" Inlet (ID) 2" Outlet (ID)

from

$83.99
Product Features:
  • EPA COMPLIANT – For use on pre-OBDII vehicles, 1995 and older. Not legal for sale or use in CA, CO and NY. Legal in ME on all pre-OBD vehicles only. Consult your state’s aftermarket converter regulations for details.
  • NO BREAK IN REQUIRED – Ready to operate with application-specific converter shell design and mat compression, no converter break in required after installation
  • DURABLE – Features stainless-steel body with aluminized pipe and heat shields for durability
  • FLEXIBLE SOLUTION – Customizable design features expandable bushings for easy fitment and may require specialized fabrication and welding for installation
  • OE-STYLE DESIGN – Features aluminized heat shields when originally equipped, to match OE design, protecting the undercarriage from heat created by the converter
  • BUY WITH CONFIDENCE – Backed by Walker’s 25,000-mile/40,000-kilometer emissions and 50,000-mile/80,000-kilometer structural integrity limited warranty. Visit Walkerexhaust.com for details.
See More

Walker – Standard EPA Universal Catalytic Converter – 2" Inlet (ID) 2" Outlet (ID) (Part No.15031)

Standard EPA Universal Catalytic Converter - 2" Inlet (ID) 2" Outlet (ID)

from

$131.99
Product Features:
  • EPA COMPLIANT – For use on pre-OBDII vehicles, 1995 and older. Not legal for sale or use in CA, CO and NY. Legal in ME on all pre-OBD vehicles only. Consult your state’s aftermarket converter regulations for details.
  • NO BREAK IN REQUIRED – Ready to operate with application-specific converter shell design and mat compression, no converter break in required after installation
  • DURABLE – Features stainless-steel body with aluminized pipe and heat shields for durability
  • FLEXIBLE SOLUTION – Customizable design features expandable bushings for easy fitment and may require specialized fabrication and welding for installation
  • OE-STYLE DESIGN – Features aluminized heat shields when originally equipped, to match OE design, protecting the undercarriage from heat created by the converter
  • BUY WITH CONFIDENCE – Backed by Walker’s 25,000-mile/40,000-kilometer emissions and 50,000-mile/80,000-kilometer structural integrity limited warranty. Visit Walkerexhaust.com for details.
See More

MagnaFlow – California Universal Catalytic Converter – 2.25" (Part No.3322305)

California Universal Catalytic Converter - 2.25"

from

$560.99
Keep the check engine light off with MagnaFlow California Grade CARB Compliant Universal Catalytic Converter 3322305. The Universal design allows the part to fit a wide array of vehicles (cutting and welding required), and the stainless steel construction of this spun body catalytic converter is highly resistant to corrosion. The single laser fusion weld of the spun body greatly reduces the possibility of a leak, and our compact, low-mass design also allows for greater thermal efficiency. This replacement part is designed to meet or exceed California Air Resource Board requirements, and has undergone additional testing to comply with CARB guidelines to allow for legal use in California and CARB restricted states, for the listed vehicles.

Product Features:
  • Your trusted source for CARB-compliant catalytic converters, providing assurance of genuine compliance while delivering quality that will last
  • Expertly formulated catalyst blend maximizes efficiency, ensuring optimal emissions control to keep your check engine light off
  • High strength 16 gauge 409 stainless steel tubing for exceptional corrosion resistance and maximum service life
  • Compact, lightweight construction enables installation in confined areas, welding is required
  • Durable 308 stainless steel MIG welds
See More

Walker – CalCat CARB Universal Catalytic Converter (Part No.81326)

CalCat CARB Universal Catalytic Converter

from

$387.99
Designed, tested and validated for assured compliance to meet CARB standards, Walker® CalCat® Universal Catalytic Converters are available for OBDII (1996 and newer) and non-OBD (1995 and older) vehicles.

Product Features:
  • SUPERIOR TECHNOLOGY — Optimal high technology washcoat formulated to deliver superior performance (as compared to EPA-compliant converters)
  • CONSISTENT PERFORMANCE — Utilizes a precise OE-style coating process to apply catalyst material to the substrate, providing consistent performance for assured emissions compliance
  • DURABLE — Features stainless-steel body with aluminized pipe and heat shields for durability
  • FLEXIBLE SOLUTION — Customizable design features expandable bushings for easy fitment and may require specialized fabrication and/or welding for installation
  • BUY WITH CONFIDENCE — Backed by Walker’s emissions and structural integrity warranty. Visit Walkerexhaust.com for details.
See More

MagnaFlow – Catalytic Converter (Part No.94004)

Catalytic Converter

from

$119.99
MagnaFlow Standard Grade Federal/EPA Compliant Universal Catalytic Converter 94004 helps keep the check engine light off. Get the right fit for a wide array of vehicles thanks to the adaptable Universal design (cutting and welding is required). With highly corrosion resistant, stainless steel construction, you can have confidence in the quality of this catalytic converter. This replacement part is designed to meet or exceed Federal emissions requirements set forth by the EPA, complying with legal standards for pre-OBDII Federally registered vehicles.

Product Features:
  • Your trusted source for EPA-compliant catalytic converters, providing assurance of genuine compliance while delivering quality that will last
  • Expertly formulated catalyst blend maximizes efficiency, ensuring optimal emissions control to keep your check engine light off
  • High strength 16 gauge 409 stainless steel tubing for exceptional corrosion resistance and maximum service life
  • Compact, lightweight construction enables installation in confined areas, welding is required
  • Durable 308 stainless steel MIG welds
See More

Walker – CalCat CARB Universal Catalytic Converter – 2" Inlet (ID) 2" Outlet (ID) (Part No.81126)

CalCat CARB Universal Catalytic Converter - 2" Inlet (ID) 2" Outlet (ID)

from

$419.99
Designed, tested and validated for assured compliance to meet CARB standards, Walker CalCat Universal Catalytic Converters are available for OBDII (1996 and newer) and non-OBD (1995 and older) vehicles.

Product Features:
  • CARB COMPLIANT – For use on OBDII vehicles, 1996 and newer and non-OBD 1995 and older. Legal for sale in CA, CO, NY & other states requiring CARB-compliant replacement converters. Consult your state’s aftermarket converter regulations.
  • SUPERIOR TECHNOLOGY – Optimal high technology wash coat formulated to deliver superior performance (as compared to EPA-compliant converters)
  • CONSISTENT PERFORMANCE – Utilizes a precise OE-style coating process to apply catalyst material to the substrate, providing consistent performance for assured emissions compliance
  • DURABLE – Features stainless-steel body with aluminized pipe and heat shields for durability
  • FLEXIBLE SOLUTION – Customizable design features expandable bushings for easy fitment and may require specialized fabrication and welding for installation
  • BUY WITH CONFIDENCE – Backed by Walker’s 50,000-mile/80,000-kilometer emissions and structural integrity limited warranty
See More

MagnaFlow – Standard Grade Universal Catalytic Converter – 2.25" (Part No.94005)

Standard Grade Universal Catalytic Converter - 2.25"

from

$119.99
MagnaFlow Standard Grade Federal/EPA Compliant Universal Catalytic Converter 94005 helps keep the check engine light off. Get the right fit for a wide array of vehicles thanks to the adaptable Universal design (cutting and welding is required). With highly corrosion resistant, stainless steel construction, you can have confidence in the quality of this catalytic converter. This replacement part is designed to meet or exceed Federal emissions requirements set forth by the EPA, complying with legal standards for pre-OBDII Federally registered vehicles.

Product Features:
  • Your trusted source for EPA-compliant catalytic converters, providing assurance of genuine compliance while delivering quality that will last
  • Expertly formulated catalyst blend maximizes efficiency, ensuring optimal emissions control to keep your check engine light off
  • High strength 16 gauge 409 stainless steel tubing for exceptional corrosion resistance and maximum service life
  • Compact, lightweight construction enables installation in confined areas, welding is required
  • Durable 308 stainless steel MIG welds
See More

Walker – CalCat CARB Universal Catalytic Converter – 2.25" Inlet (ID) 2.25" Outlet (ID) (Part No.81127)

CalCat CARB Universal Catalytic Converter - 2.25" Inlet (ID) 2.25" Outlet (ID)

from

$464.99
Designed, tested and validated for assured compliance to meet CARB standards, Walker CalCat Universal Catalytic Converters are available for OBDII (1996 and newer) and non-OBD (1995 and older) vehicles.

Product Features:
  • CARB COMPLIANT – For use on OBDII vehicles, 1996 and newer and non-OBD 1995 and older. Legal for sale in CA, CO, NY & other states requiring CARB-compliant replacement converters. Consult your state’s aftermarket converter regulations.
  • SUPERIOR TECHNOLOGY – Optimal high technology wash coat formulated to deliver superior performance (as compared to EPA-compliant converters)
  • CONSISTENT PERFORMANCE – Utilizes a precise OE-style coating process to apply catalyst material to the substrate, providing consistent performance for assured emissions compliance
  • DURABLE – Features stainless-steel body with aluminized pipe and heat shields for durability
  • FLEXIBLE SOLUTION – Customizable design features expandable bushings for easy fitment and may require specialized fabrication and welding for installation
  • BUY WITH CONFIDENCE – Backed by Walker’s 50,000-mile/80,000-kilometer emissions and structural integrity limited warranty
See More

Walker – Standard EPA Universal Catalytic Converter – 2.25" Inlet (ID) 2.25" Outlet (ID) (Part No.15037)

Standard EPA Universal Catalytic Converter - 2.25" Inlet (ID) 2.25" Outlet (ID)

from

$111.99
Product Features:
  • EPA COMPLIANT – For use on pre-OBDII vehicles, 1995 and older. Not legal for sale or use in CA, CO and NY. Legal in ME on all pre-OBD vehicles only. Consult your state’s aftermarket converter regulations for details.
  • NO BREAK IN REQUIRED – Ready to operate with application-specific converter shell design and mat compression, no converter break in required after installation
  • DURABLE – Features stainless-steel body with aluminized pipe and heat shields for durability
  • FLEXIBLE SOLUTION – Customizable design features expandable bushings for easy fitment and may require specialized fabrication and welding for installation
  • OE-STYLE DESIGN – Features aluminized heat shields when originally equipped, to match OE design, protecting the undercarriage from heat created by the converter
  • BUY WITH CONFIDENCE – Backed by Walker’s 25,000-mile/40,000-kilometer emissions and 50,000-mile/80,000-kilometer structural integrity limited warranty. Visit Walkerexhaust.com for details.
See More

Walker – CalCat CARB Universal Catalytic Converter (Part No.81327)

CalCat CARB Universal Catalytic Converter

from

$396.99
Designed, tested and validated for assured compliance to meet CARB standards, Walker® CalCat® Universal Catalytic Converters are available for OBDII (1996 and newer) and non-OBD (1995 and older) vehicles.

Product Features:
  • SUPERIOR TECHNOLOGY — Optimal high technology washcoat formulated to deliver superior performance (as compared to EPA-compliant converters)
  • CONSISTENT PERFORMANCE — Utilizes a precise OE-style coating process to apply catalyst material to the substrate, providing consistent performance for assured emissions compliance
  • DURABLE — Features stainless-steel body with aluminized pipe and heat shields for durability
  • FLEXIBLE SOLUTION — Customizable design features expandable bushings for easy fitment and may require specialized fabrication and/or welding for installation
  • BUY WITH CONFIDENCE — Backed by Walker’s emissions and structural integrity warranty. Visit Walkerexhaust.com for details.
See More

MagnaFlow – California Universal Catalytic Converter – 2.00" (Part No.3322304)

California Universal Catalytic Converter - 2.00"

from

$560.99
Keep the check engine light off with MagnaFlow California Grade CARB Compliant Universal Catalytic Converter 3322304. The Universal design allows the part to fit a wide array of vehicles (cutting and welding required), and the stainless steel construction of this spun body catalytic converter is highly resistant to corrosion. The single laser fusion weld of the spun body greatly reduces the possibility of a leak, and our compact, low-mass design also allows for greater thermal efficiency. This replacement part is designed to meet or exceed California Air Resource Board requirements, and has undergone additional testing to comply with CARB guidelines to allow for legal use in California and CARB restricted states, for the listed vehicles.

Product Features:
  • Your trusted source for CARB-compliant catalytic converters, providing assurance of genuine compliance while delivering quality that will last
  • Expertly formulated catalyst blend maximizes efficiency, ensuring optimal emissions control to keep your check engine light off
  • High strength 16 gauge 409 stainless steel tubing for exceptional corrosion resistance and maximum service life
  • Compact, lightweight construction enables installation in confined areas, welding is required
  • Durable 308 stainless steel MIG welds
See More

Most Popular Catalytic Converters for 1977 Mercury Comets

Enhance your 1977 Mercury Comet with one of the 6 Catalytic Converters we have in stock, starting at just $83.99.

Walker – Standard EPA Universal Catalytic Converter – 2" Inlet (ID) 2" Outlet (ID) (Part No.15031)

Standard EPA Universal Catalytic Converter - 2" Inlet (ID) 2" Outlet (ID)

from

$131.99
Product Features:
  • EPA COMPLIANT – For use on pre-OBDII vehicles, 1995 and older. Not legal for sale or use in CA, CO and NY. Legal in ME on all pre-OBD vehicles only. Consult your state’s aftermarket converter regulations for details.
  • NO BREAK IN REQUIRED – Ready to operate with application-specific converter shell design and mat compression, no converter break in required after installation
  • DURABLE – Features stainless-steel body with aluminized pipe and heat shields for durability
  • FLEXIBLE SOLUTION – Customizable design features expandable bushings for easy fitment and may require specialized fabrication and welding for installation
  • OE-STYLE DESIGN – Features aluminized heat shields when originally equipped, to match OE design, protecting the undercarriage from heat created by the converter
  • BUY WITH CONFIDENCE – Backed by Walker’s 25,000-mile/40,000-kilometer emissions and 50,000-mile/80,000-kilometer structural integrity limited warranty. Visit Walkerexhaust.com for details.
See More

MagnaFlow – Catalytic Converter (Part No.94004)

Catalytic Converter

from

$119.99
MagnaFlow Standard Grade Federal/EPA Compliant Universal Catalytic Converter 94004 helps keep the check engine light off. Get the right fit for a wide array of vehicles thanks to the adaptable Universal design (cutting and welding is required). With highly corrosion resistant, stainless steel construction, you can have confidence in the quality of this catalytic converter. This replacement part is designed to meet or exceed Federal emissions requirements set forth by the EPA, complying with legal standards for pre-OBDII Federally registered vehicles.

Product Features:
  • Your trusted source for EPA-compliant catalytic converters, providing assurance of genuine compliance while delivering quality that will last
  • Expertly formulated catalyst blend maximizes efficiency, ensuring optimal emissions control to keep your check engine light off
  • High strength 16 gauge 409 stainless steel tubing for exceptional corrosion resistance and maximum service life
  • Compact, lightweight construction enables installation in confined areas, welding is required
  • Durable 308 stainless steel MIG welds
See More

Walker – Standard EPA Universal Catalytic Converter – 2" Inlet (ID) 2" Outlet (ID) (Part No.15036)

Standard EPA Universal Catalytic Converter - 2" Inlet (ID) 2" Outlet (ID)

from

$83.99
Product Features:
  • EPA COMPLIANT – For use on pre-OBDII vehicles, 1995 and older. Not legal for sale or use in CA, CO and NY. Legal in ME on all pre-OBD vehicles only. Consult your state’s aftermarket converter regulations for details.
  • NO BREAK IN REQUIRED – Ready to operate with application-specific converter shell design and mat compression, no converter break in required after installation
  • DURABLE – Features stainless-steel body with aluminized pipe and heat shields for durability
  • FLEXIBLE SOLUTION – Customizable design features expandable bushings for easy fitment and may require specialized fabrication and welding for installation
  • OE-STYLE DESIGN – Features aluminized heat shields when originally equipped, to match OE design, protecting the undercarriage from heat created by the converter
  • BUY WITH CONFIDENCE – Backed by Walker’s 25,000-mile/40,000-kilometer emissions and 50,000-mile/80,000-kilometer structural integrity limited warranty. Visit Walkerexhaust.com for details.
See More

Walker – CalCat CARB Universal Catalytic Converter – 2" Inlet (ID) 2" Outlet (ID) (Part No.81126)

CalCat CARB Universal Catalytic Converter - 2" Inlet (ID) 2" Outlet (ID)

from

$419.99
Designed, tested and validated for assured compliance to meet CARB standards, Walker CalCat Universal Catalytic Converters are available for OBDII (1996 and newer) and non-OBD (1995 and older) vehicles.

Product Features:
  • CARB COMPLIANT – For use on OBDII vehicles, 1996 and newer and non-OBD 1995 and older. Legal for sale in CA, CO, NY & other states requiring CARB-compliant replacement converters. Consult your state’s aftermarket converter regulations.
  • SUPERIOR TECHNOLOGY – Optimal high technology wash coat formulated to deliver superior performance (as compared to EPA-compliant converters)
  • CONSISTENT PERFORMANCE – Utilizes a precise OE-style coating process to apply catalyst material to the substrate, providing consistent performance for assured emissions compliance
  • DURABLE – Features stainless-steel body with aluminized pipe and heat shields for durability
  • FLEXIBLE SOLUTION – Customizable design features expandable bushings for easy fitment and may require specialized fabrication and welding for installation
  • BUY WITH CONFIDENCE – Backed by Walker’s 50,000-mile/80,000-kilometer emissions and structural integrity limited warranty
See More

MagnaFlow – California Universal Catalytic Converter – 2.00" (Part No.3322304)

California Universal Catalytic Converter - 2.00"

from

$560.99
Keep the check engine light off with MagnaFlow California Grade CARB Compliant Universal Catalytic Converter 3322304. The Universal design allows the part to fit a wide array of vehicles (cutting and welding required), and the stainless steel construction of this spun body catalytic converter is highly resistant to corrosion. The single laser fusion weld of the spun body greatly reduces the possibility of a leak, and our compact, low-mass design also allows for greater thermal efficiency. This replacement part is designed to meet or exceed California Air Resource Board requirements, and has undergone additional testing to comply with CARB guidelines to allow for legal use in California and CARB restricted states, for the listed vehicles.

Product Features:
  • Your trusted source for CARB-compliant catalytic converters, providing assurance of genuine compliance while delivering quality that will last
  • Expertly formulated catalyst blend maximizes efficiency, ensuring optimal emissions control to keep your check engine light off
  • High strength 16 gauge 409 stainless steel tubing for exceptional corrosion resistance and maximum service life
  • Compact, lightweight construction enables installation in confined areas, welding is required
  • Durable 308 stainless steel MIG welds
See More

Walker – CalCat CARB Universal Catalytic Converter (Part No.81326)

CalCat CARB Universal Catalytic Converter

from

$387.99
Designed, tested and validated for assured compliance to meet CARB standards, Walker® CalCat® Universal Catalytic Converters are available for OBDII (1996 and newer) and non-OBD (1995 and older) vehicles.

Product Features:
  • SUPERIOR TECHNOLOGY — Optimal high technology washcoat formulated to deliver superior performance (as compared to EPA-compliant converters)
  • CONSISTENT PERFORMANCE — Utilizes a precise OE-style coating process to apply catalyst material to the substrate, providing consistent performance for assured emissions compliance
  • DURABLE — Features stainless-steel body with aluminized pipe and heat shields for durability
  • FLEXIBLE SOLUTION — Customizable design features expandable bushings for easy fitment and may require specialized fabrication and/or welding for installation
  • BUY WITH CONFIDENCE — Backed by Walker’s emissions and structural integrity warranty. Visit Walkerexhaust.com for details.
See More

Top-Rated Catalytic Converter Brands For Your 1977 Mercury Comet

When it comes to finding the perfect Catalytic Converter for your 1977 Mercury Comet, Advance Auto Parts has you covered with a wide selection of high-quality OEM and aftermarket options from 2 trusted brands. We carry the most popular Catalytic Converter brands including Walker, and more, all known for their exceptional customer ratings (average brand rating of 4.2 stars) and competitive prices, as low as $131.99. Purchasing a Catalytic Converter from us here at Advance Auto Parts is a smart move for both you and your 1977 Mercury Comet, providing peace of mind with parts that meet or exceed OEM standards.

Popular Walker 1977 Mercury Comet Catalytic Converters

If you’re looking for a top-quality Catalytic Converter for your 1977 Mercury Comet, Advance Auto Parts has exactly what you need with our selection of Walker Catalytic Converters. We have 1 Walker Catalytic Converters in stock for this fitment, all known for their durability and precision fit. With prices starting at just $131.99, you’ll find the perfect Catalytic Converter for your needs and budget. Walker Catalytic Converters for the 1977 Mercury Comet come highly rated, with over 1 customer reviews and an impressive average rating of 4.2 stars. Choosing a Walker Catalytic Converter from Advance Auto Parts is a smart move to ensure quality and value for your vehicle.
Standard EPA Universal Catalytic Converter - 2" Inlet (ID) 2" Outlet (ID)
from $131.99
(1)
Standard EPA Universal Catalytic Converter – 2" Inlet (ID) 2" Outlet (ID)
“had it installed by professional”

FAQs for 1977 Mercury Comet Catalytic Converters

What are the best-selling Catalytic Converters for 1977 Mercury Comets?

Out of 6 Catalytic Converters that fit 1977 Mercury Comets, the following parts are the top sellers:

What’s the price range for 1977 Mercury Comet Catalytic Converters?

The prices of Catalytic Converters for the 1977 Mercury Comet range from $83.99 up to $560.99 for the most premium parts.

What is the average price of a Catalytic Converter for a 1977 Mercury Comet?

The average price for Catalytic Converters for the 1977 Mercury Comet is $293.11. Keep in mind the variety of part types within our Catalytic Converter category, where you are likely to find a wide range of prices across a variety of parts and components.

What are the cheapest Catalytic Converters for my 1977 Mercury Comet?

Does Advance Auto Parts sell Catalytic Converters for any other 1977 Mercury models?

Yes. We stock Catalytic Converters for 3 other popular 1977 Mercury models. Some of the most popular are 1977 Cougar Catalytic Converters, 1977 Capri Catalytic Converters, 1977 Monarch Catalytic Converters, and 1977 Bobcat Catalytic Converters.

What are the top-rated Catalytic Converters that fit the 1977 Mercury Comet?

The one 1977 Mercury Comet Catalytic Converter we have in stock is the Standard EPA Universal Catalytic Converter – 2" Inlet (ID) 2" Outlet (ID). It costs $83.99.

What types of Catalytic Converters do you sell for my 1977 Mercury Comet?

We currently have just 1 Catalytic Converter in stock for a 1977 Mercury Comet, and as of 11/2/25, it is a Catalytic Converter.

Can I get help with 1977 Mercury Comet Catalytic Converter orders?

Contact our customer support team by chat or phone, through the help desk page, where you can find instant answers about Mercury Catalytic Converters and more.

What is your return policy for Mercury Comet Catalytic Converters?

Advance Auto Parts keeps returns simple. For new Mercury Comet Catalytic Converters and accessories, your online orders can be returned, in their original condition, within 45 days. For requirements, see the returns page.