Higher volume helps reduce engine and oil temperatures. 39mm diameter rotors for maximum performance (Std=38mm). 110% Feed and 115% Scavenge volume compared to stock. High quality die-cast aluminum body construction with a high-strength powder metal gear.Includes all necessary hardware and gaskets. If you need something that you don't see listed just ask. This applies only to orders in the continental U. Serious injury, death, and property damage can result from the improper use, control, alteration, or maintenance of motorcycles. The dealer and dealers' customers must exercise good judgment in the use, control, alteration, part selection and installation, and maintenance, of motorcycles. Jireh has no control over the judgment of others and assumes no responsibility or liability of any nature for the failure of others to use good judgment.