1、Applicable Model: Specially designed for 49cc 66cc 80cc Engine Motorized Bicycle Bike. Please confirm whether your model is applicable before buying. 2、Function: Pulley tensioner roller can reduce the pressure on the chain, ensuring consistent tension, and can provide a smoother riding experience. 3、Sturdy Build: Constructed from high strength materials, these pulley tensioner rollers are resistant to deformation and cracking, ensuring long lasting durability. 4、Direct Replacement: Easy to install as a direct replacement, the pulley tensioner roller offers a fast solution for replacing damaged original parts. 5、Package Includes: You will receive pair of pulley tensioner, with 9mm installation inner diameter, is a necessary accessory for Motorized Bicycle Bike. Item Type: Chain Roller Material: ABS+metal Installation Inner Diameter: Approx. 9mm / 0.35in Quantity: 1 pair Fitment: Fit for 49cc 66cc 80cc Motorized Bicycle Bike, can be installed if the size is suitable 1 x Pair of Chain Roller