Features1Alignment Tool: A correction tool used for the alignment of bike rear derailleur, which ensures higher cycling safety and stability. 2Using Tips: Directly screw the tool into chain lifter hanger. There is a gauge on the rod to measure the distance to the wheel. Then, as the wheel rotates the gauge to 90 Degree, 180 Degree, 270 Degree and 360 Degree, note any differences in the measured values. Align the derailleur hanger by applying pressure to the tool arm. The results can be checked immediately. 3Good in Design: Comes with 400mm length, the tool enables simple operation, largely simplifying your working and improving efficiency. 4Great Material: Adopting aluminium alloy material with a sturdy structure, not easy to deform and very durable for long using. 5Easy Carrying: Light in weight and compact in size as well, the tool can be conveniently carried for both indoor and outdoor work.SpecificationItem Type: Derailleur Hanger Alignment GaugeMaterial: Aluminium AlloyLength: Approx. 400mm / 15.75inPackage List1 x Derailleur Hanger Alignment Gauge3 x Accessory