Quad Works 24-Q425 Stage-1 Kit for Yamaha YXR660F For Yamaha YXR 660 Rhino 04-07 Boost throttle response and increase horsepower by 10-15 percentage with the Quad Works Stage-1 power kit These kits are designed to be adjustable for use with aftermarket or stock exhausts and for all altitudes Includes a cleanable and reusable high-flow stock replacement air filter, Outerwears prefilter, and Dynojet jet-kit Comes with instructions and all necessary hardware