Kit includes front and rear sprocket with same gear ratios as stock and a Gold Renthal R1-428 chain, Saves more than 2 lb. over the stock 520 O-ring chain and steel rear sprocket, Improves acceleration and responsiveness with less revolving un-sprung weight, Front sprocket is made from super strong nickel chromoly and is grooved to clear mud and increase chain life, Rear sprocket is made from 7075 T-6 aluminum which is precision machined with self-cleaning mud grooves and lightening holes