Made of extruded aluminum for durability and long life. Piston type free floating valves reduce O-ring wear. Easy grip front facing knobs. Gauges include R134a Fahrenheit scale in SAE and Kpa measurements. Anti-flutter gauges smooth out needle movement This aluminum manifold set includes 90 degree Snap-N-Seal couplers. Other features include extra access port for vacuum line, extra large sight glass for visual check of refrigerant and gauges can be calibrated to maintain accuracy.