Bike Hook Aligner Bicycle Derailleur Aligner Hanger Bike Tail Hook 360 Rotation Alignment Corrector Cycling Repair Tools Feature: Used to correct rear derailleur lugs have solved many transmission shifting problems, especially positioning rear derailleur systems. Features: stainless steel body, electroplated heat treatment, high strength, corrosion resistance, 360 rotating correction, cnc turning and milling threads, tight fit, plum rotating handle, easy adjustment of the measuring rod. Made of stainless steel, electroplating heat treatment, high hardness and corrosion resistance. Precision thread, tight fit, clockwise rotation of the positioning knob, screw the bolt into the rear change lugs to lock. Lock and press the sliding bracket to adjust the distance between the measuring rod and the hub, and measure the deviation between the tail hook and the wheel rim. Take the swivel rod as the axis and rotate 360 to measure the distance between the wheel rim and the tail hook and correct the tail hook. Positioning o-ring: move the measuring rod to touch the wheel rim, and position the o-ring by pressing the sliding bracket flush while moving the o-ring. Specification: Name: Bike Tail Hook Corrector Color: Silver White Material: Stainless Steel Weight: About 1062g / Box Package Size: 430*100*70mm/16.93*3.94*2.76in Function: used to correct the rear shift lugs have solved many transmission shifting problems, especially positioning the rear shifting 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.