FunctionKeep the chain taut and away from the frame and paint. Prevents friction between the chain and the body during transportation and causes scratches. Nylon MaterialThe drum main body is made of nylon with built-in bearings. Does not damage the chain. Note that the drum will follow when the chain moves Easy to disassemble and installQuick release design can be quickly installed and disassembled. It is used to maintain the tension of the chain when cleaning the chain or transporting the bicycle, to prevent friction between the chain and the body and cause scratches. Convenient and flexible It allows the bike to be moved with the wheel removed and the derailleur can be moved. High Compatibility Works with all 8mm derailleurs and chains. Compatible with 12mm quick release and thru axle bike frames. Features: 1. Quick release lever allows quick installation and removal. 2.High quality of materials. 3.Lightweight and mini size. Specification: Material: Nylon Color: As Pictures Show Dimensions: 7x6.5cm/2.76x2.56 inches Weight: 50g Quantity: 1 piece Package includes: 1 x keeper of bicycle chain