Description: Fitment：For Razor MX500 Dirt Rocket (versions 22+), MX650 Dirt Rocket (versions 15+), SX500 (versions 1+) and RSF350 electric motocross bike. Easy to install：Long-term use can lead to chain loosening and wear, the kit provides heavy-duty #25 Roller Chain 132L and an additional 8 links of chain and chain tensioner, eliminating the need to order parts one by one for easy replacement or repair. Function:Our sturdy rear sprocket with 80 teeth provides optimal power transmission and guarantees you long lasting use.. Meet the requirements for use in a variety of terrains:Our chain plate guides effectively prevent your chain from derailing, whether you are racing on the track or dealing with rough terrain, so that you have a comfortable riding experience. Package include：1 x Rear sprocket and freewheel chain plate guide assembly,1 x #25 Roller 132L Chain, 8 x master link, 1 x chain tensioner, 1 x spring.