Litens was the Original Equipment (O.E.) supplier of this Ford/Mercury tensioner and offers this "O.E. Exact"* part for the aftermarket. This "O.E. Exact"* part for the aftermarket meets all original equipment form, fit, and function specifications. *(O.E. Exact - Original Equipment manufacturers prohibits the use of their part number or logo on parts sold to other customers. Therefore, the Litens aftermarket part may have minor cosmetic differences but still be exact in performance and design). The Litens aftermarket part has upgraded the pulley to a to a 35 spoke configuration for a smoother running surface than the original design. Choosing The Correct Replacement Part: Both the original equipment and Litens aftermarket tensioner use a round spring versus a flat spring. Litens is the world's largest supplier of original equipment (O.E.) power transmission products. At Litens, we design systems that are more efficient, resulting in tangible fuel economy/emissions benefits. Litens holds over 2000 patents and continues to respond to the ever-changing automotive industry by investing heavily in new technology, facilities, and people. 90% of our line is made of products coming from the OE manufacturer, which makes the Litens Tensioning Products portfolio the purest OE tensioning line in the North American aftermarket.