Chain & Sprocket Kit Contents: 13T Front Sprocket - SPF210313C 48T Rear Sprocket - SPR27048C 114 Link RK Chain - RKPGB520MXUX114 RK Kit Box - SPRKITBOX RK chain and sprocket kits are the perfect drive maintenance kit for your bike, including a strong and durable 13T front and 48T rear steel sprocket, constructed from SCM420 chromoly steel alloy (front) & C45 high carbon steel with a electroplated Zinc finish (rear) paired with a high-quality UW-ring RK chain this kit has everything you need to replace your old warped and stretched chain and sprockets. The perfect alternative to expensive OEM replacements while designed to meet and exceed OEM specifications. Supplied in presentable packaging with a carry handle for convenient transportation. About the Chain: Featuring RK's Ultra Thin Seal technology, the seal thickness of the MXU series UW-rings are less than 50% of the common seal. Made for professional enduro/motocross racers. The UW-rings significantly improve chain life by lowering friction over your conventional heavy duty chain, while the ultra thin seals reduce weight compared to a O or X-ring chain. Fits: Yamaha YZ125 2005-2009 2011-2020 YZ250F 2001-2007 2009 2011-2018