Description: 【Functional】: Bike single speed conversion kit can change multi speed bike into single speed bike. 【Premium and Reliable】: Bike chain tensioner and kit packages are made of high quality aluminum alloy and stainless steel material, which is wear resistant, sturdy, and durable. 【High Performance】: Ensures perfect tension for your chain to make you pedal with less effort, suitable for long time outdoor riding. 【Easy Installation】: This chain tensioner kit mounts right onto a mountain bike derailleur hanger to provide a simple, effective, and adjustable way to tension a single speed system. 【Package Contains】: 5 Spacers, 1 Flywheel Cover, 1 Flywheel, 1 Double Guide Wheel Chain Tensioner, 3 Wrenches, 1 Torque Adjuster. Specification: Material: Aluminum Alloy, Stainless Steel Size Chart: 10cmx6.4cmx2.75cm/3.94inchx2.52inchx1.08inch Package Includes: 5 Base Spacers 1 Flywheel Cover 1 Flywheel 1 Double Guide Wheel Chain Tensioner 3 Wrenches 1 Torque Adjuster Note: Please allow slightly errors due to manual measurement and different monitors.