The Feedback Sports Chain Keeper is an elegant and highly functional maintenance accessory that will help you work on your bicycle like a pro. CNC Machined aluminum, Delrin roller, three year manufacturer's warranty. Features: Retains chain tension after the rear wheel is removed Fits road, cyclocross, and mountain bike Compatible with standard QR & 12mm thru-axle dropouts For maintenance, washing, travel & storage Specifications: Weight: 1lb Dimensions: 6 x 4 x 4 inches