FASS Diesel Fuel Systems are engineered, manufactured, and assembled in the U.S.A. and we wouldn’t have it any other way. Diesel Performance Products aren’t just an accessory, they are a way of life; As is the reliability of an American Made product. FASS provides the cleanest fuel to the vehicles powering the infrastructure of our great nation, whether it’s a Class 8 Semi hauling Pittsburgh Steel, or a Diesel Pickup in cattle country, FASS is built to last. Constructed from 6061 T-6 Aircraft Quality Aluminum, and boasting such proprietary features as FASS Silencing Technology (FST), Performance Radius Cuts (PRC), and Mass Flow Return (MFR), FASS is truly a step above the rest, in both cutting edge technology and quality.