Cab Rear Compressed Natural Gas Fuel System: Our proprietary lightweight Q-Lite® IV technology is designed for medium and heavy trucks, is aerodynamically invisible and is critical to increasing payload and reducing vehicle load. Very effective when important. Features: Three ultra-light Q-Lite® tanks for 123.6 DGE, 160 DGE and 180 DGE, aerodynamic design, expandable with Q-Rail frame-rail mount fuel system, easy "hook-on" installation, high-quality OEM system, 2-year 200,000-mile warranty