Description: With simple design, the tail hook correction tool is easy to use. After locking the tool in the rear variable lifting eye, the distance to the wheel can be marked on the gauge. When turning the gauge to the C D direction of the wheel, and the position does not exceed 4mm to detect whether there is difference between the distance of the gauge and the wheel, then you can get the result immediately. With practical functions, the tail hook correction tool can help solve a multitude of derailleur shifting problems, especially index shifting systems. Made of stainless steel material, the tail hook correction tool has high temperature resistance of 800 Celsius degree, which is , anti-rust and wear-. Color: silver Material: Stainless steel Package Contents: 1 x Bike Tail Hook Corrector Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.