Neuspeed's lightweight crankshaft pulley is made from 6061 T6 aluminum and hardcoat anodized for durability. The lighter and slightly smaller diamter pulley consumes less power to run your accesories. Each kit includes a new crankshaft pulley, shorter belt, and 6 M8x16mm hex head bolts. Neuspeed recorded gains of 5-7hp and improved throttle response. Its an easy install and a great idea if you need to replace your serpentine belt anyways as a new one is included.