The MotoSport.com Mika Metals Chain & Hybrid Sprocket Kit includes ONE Mika Metals Front Sprocket, ONE Mika Metals Hybrid Rear Sprocket, and your choice of ONE Mika Metals Drive Chain, each with the following features: Mika Metals Front Sprocket: Mika sprockets are made of the highest quality steel to withstand the rigors of off-road racing. Hardened steel for ultra-long lasting wear. High quality replacement for you stock sprocket. Self-cleaning grooves to improve sprocket life. Tooth design allows for increased power transfer. Drilled (certain applications) for light weight. Mika Metals Hybrid Rear Sprocket: Mika Metals Hybrid Sprockets are the ultimate application in lightweight long lasting sprockets. Its unique design means the majority of the sprocket is made from aerospace aluminum, while the teeth are made from hardened steel.