Fit 49cc 66cc 80cc 2 Stroke Engine Motorized Bicycle Spring Loaded Chain Tensioner Eletric Bike Black Chain Tensioner Kit Feature: Spring loaded chain tensioner that keeps chain from popping and snapping. Can_x000D_ be used for all chain drive applications including center mount and _x000D_ rear mount chain drive for gas motorized bicycle plan kits. Must_x000D_ be mounted so that it pulls on the chain so the spring action will work_x000D_ effectively keeping the chain tight, but not too tight. Spring loaded installation positions on bicycle so the spring pulls on the chain. Can also be placed on the lower chain. The_x000D_ amount of tension can be adjusted to your liking. Remove vibration and _x000D_ snapping and popping of the chain during operation. It also keeps the _x000D_ nylon tension wheel from wearing out. This_x000D_ makes for a smoother, more enjoyable ride without vibration and _x000D_ increases the lifespan of not only the chain, but motorized bicycle _x000D_ parts. Makes_x000D_ the whole bike, motor and everything else last longer, because you _x000D_ aren't shaking it excessively. It really makes the difference between _x000D_ enjoying your ride and being glad that it was over. Specifications: Product Name: Chain tensioner wheel Usage:For 49/66/80cc Engine Motorized Bike Condition:Brand New Material:Metal Size:as picture show Color:Black Package included: 1 * Chain tensioner wheel _x000D_ _x000D_ _x000D_