HIGH QUALITY MATERIAL - This bicycle chain tensioner is made of high quality and galvanized iron, which is strong and durable, not easy to rust and has a long service life. It is a good choice for bicycle tools. MAIN FUNCTION - Bicycle tensioner tension adjustment screw, a tool for fixing bicycle chain. This bicycle chain tensioner is used to prevent the rear wheel from slipping forward under pressure. EASY TO USE - The adjuster is used to adjust the tension on the rear wheel of the bike. It can prevent the chain slack of childrens bicycles, single-speed bicycles. A single unit is enough to hold the wheel in place. WIDE USE - This bike adjuster is suitable for trails with chainstays, mountain bikes and stationary bikes. Suitable for single speed bikes and stationary bikes. EASY TO INSTALL - This bicycle chain tensioner is lightweight and easy to carry and install. Floating pulleys and springs perfectly adjust the chain tension to make the bike even tighter.