Description: 【Package Contains】There are 1 Chain Tensioner, 1 Torque Adjuster, 1 Freewheel, 5 Freewheel Washer, 1 Freewheel Cover and 3 Wrenches in package. 【Double Guide Wheel Design】Bike Chain Tensioner is double guide wheel chain tensioner, making the chain less likely to fall off, more securely biking. 【Torque Regulator】Torque Adjuster can be selected the corresponding hole position as needed to adapt to different chain lengths and torques. 【Premium Material】Bike Chain Tensioner Accessories are made of high quality aluminum alloy and stainless steel material, sturdy and durable. 【Please Notice】1. Adjust the center of the chain guide and the center of the rear flywheel to keep them on the same horizontal line as much as possible 2. The angle of the guide wheel after installation cannot be parallel or lower than the horizontal line The chain is inserted into the guide wheel as shown in the picture, so that each guide wheel can play its role and the chain will not fall off easily. Specification: Material: Aluminum Alloy Stainless Steel Size Chart: 10cmx6.4cmx2.65cm/3.94inchx2.52inchx1.04inch Package Includes: 1 Freewheel 1 Chain Guide 1 Freewheel Cover 1 Torque Adjuster 5 Freewheel Washer 3 Wrenches Note: 1. Please allow slightly error due to manual measurement. 2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. 3. Wish you a wonderful on line shopping!