Simson chain tensioner With these chain tensioners you can easily tension your chain to the correct tension. Mount the chain tensioners with the ring around the rear wheel axle and place the bracket against the rear fork. Use the nuts to turn the rear wheel backwards and tension the chain. Specifications: Color: silver Material: steel Thread length: 35 mm Thread thickness: 6 mm Hole diameter: 10.5 mm Total length: 65 mm Weight per piece: 15 grams Product type: 020908 Contents: 2 Chain tensioners