1. Perfect Fitment: Fit for 49cc 66cc 80cc Engine Motorized Bike, a good replacement for bike. 2. High Quality: Keeps chain from popping and snapping. Made of high quality material, not easy to bend deformation. 3. Application: Can be used for all chain drive applications including center mount and rear mount chain drive for gas motorized bicycle plan kits. 4. Function: Ensures proper chain tension and alignment, prevents the chain derailment, excess wearing of the sprocket and prolongs chain's life. 5. Practiacal: Lightweight and compact design, safe and easy to use. Strong compatibility and high practicability. Product net weight: 337g Colour: Black material: metal Quantity: 1set Packing list: 1*chain tensioner Only the above package contents are included, other products are not included. Note: Reflection of light and different monitors may cause the item's color to be slightly different from the actual item. Measurements allow +/- 1-3 cm.