AEM Tru-Power Pulleys increase horsepower by decreasing the parasitic effects that factory accessory pulleys have on a vehicle's engine. The pulley's lightweight 6061 T-6 billet aluminum construction reduces rotating weight and increases efficiency. All pulleys have a tooth profile that is guaranteed to match Original Equipment (O.E.) specifications, eliminating the chances of premature belt wear. Each Tru-Power pulley kit includes comprehensive instructions, performance belts and AEM decal.