Item Type: Bicycle Chain Tensioner_x000D_ Material: Aluminum Alloy_x000D_ Application: Folding bicycles, single speed bicycles and stationary bicycles._x000D_ Function: Adjust the tightness of the chain_x000D_ Size: _x000D_ Screw: Approx. 24 x 20 x 4mm / 0.9 x 0.8 x 0.2in_x000D_ Chain Tensioner Accessories: Approx. 23 x 11 x 5mm / 0.9 x 0.4 x 0.2in, 20 x 11 x 11.5mm / 0.8 x 0.4 x 0.5in 1Avoid Chain Skipping: The inner tube of the frame can adopt a single speed chain tensioner, which can effectively avoid chain skipping and ensure safe and stable cycling. 2Adjust Tightness Of Chain: Bike chain adjuster is suitable for folding bicycles, single speed bicycles and stationary bicycles, used to adjust the tightness of the chain. 3Fine Workmanship: Precise structure, exquisite craftsmanship, attention to detail, an important tool for adjusting bicycle chains, equipped with screws for easy operation. 4Multiple Applicable Occasion: Light weight, no extra burden on the bicycle, easy to store and carry, can be easily put into your bag, suitable for home, bicycle repair shop, travel, etc. 5Aluminum Alloy Material: Bicycle chain tensioner is made of high quality aluminum alloy material, firm and sturdy, stable and wear resistant, durable for long term use. 2 x Chain Tensioner Accessories 2 x Screw Please allow slight error due to manual measurement. Thanks for your understanding.