TOOPRE Mountain Bike Tail Hook Aligner Professional Bicycle Derailleur Hanger Alignment Corrector Cycling Repair Tools Feature: The round straightening rod is made of aluminum alloy material, anodized, and the hardness is enhanced while reducing the weight. Aluminum alloy anti-slip detachable handle, precision CNC turning and milling thread, tight fit, rotate the positioning handle clockwise, screw the bolt in and then change the lifting lug to lock. Tighten the sliding bracket to adjust the distance between the measuring rod and the wheel hub, and measure the deviation between the tail hook and the wheel rim. 360° rotation correction, take the rotating rod as the axis, rotate 360°, measure the distance between the rim and the tail hook, and correct the tail hook. The measuring rod is made of stainless steel, with clear scale and accurate measurement. Move the measuring rod to contact the rim, and then move the O-ring against the sliding bracket to position it. Specification: Name: Bicycle tail hook correction tool Material: Aluminum alloy + stainless steel Packing size: 445x110x40mm/17.52x4.33x1.57in Weight: about 483g/box Function: It is used to correct the bicycle frame tail hook to solve the problem of many derailleurs, especially the positioning rear derailleur system. Note: Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! Please allow 1-2cm measuring deviation due to manual measurement.