Features: 1.Inner diameter: 8mm 2.Brand new chain rolloer 3.Dirtbike nylon chain roller wheel complete with heavy duty bearings ready to use 4.This part attached the the swing arm; the chain then runs over it to keep it aligned 5.Vary colors for you to choose your favorite one Specification: Features:_x000D_ 1. Brand new chain roller._x000D_ 2. Dirtbike nylon chain roller wheel complete with heavy duty bearings ready to use._x000D_ 3. This part attached the swing arm; the chain then runs over it to keep it aligned._x000D_ 4. Can also be used on gas petrol motorized bicycle conversions kits._x000D_ _x000D_ Specifications:_x000D_ Inner Diameter: Approx. 8mm / 0.31"_x000D_ Outside Diameter: 3.5cm / 1.38"_x000D_ Total Length: 3.5cm / 1.38"_x000D_ Package Weight: Approx. 55g_x000D_ Optional Color: Yellow, blue, green, red_x000D_ _x000D_ Package Included:_x000D_ 1 x Drive Chain Roller_x000D_ _x000D_ Note:_x000D_ 1. Please allow 1-3mm error due to manual measurement. Thanks for your understanding. _x000D_ 2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard._x000D_ 3. Please be carefully check the parts appearance, size, shape and then compare your original goods for compatibility before ordering, Thank you. _x000D_ PackageList: