Dresco universal chain tensioners With the Dresco chain tensioners you can easily bring the bicycle chain back to the correct tension. These traditional tensioners are attached to the axle of the rear wheel with the ring and the brackets rest against the rear fork. By tightening the nut, the rear wheel moves backwards so that the chain is tensioned. Tighten both nuts evenly so that the rear wheel is straight. Make sure that the chain still has some play for smooth running. Specifications: Color: silver Material: steel Dimensions: 62 mm Contents: 2 Chain tensioners