Feature:1. Alignment Tool: A correction tool used for the alignment of bike rear derailleur, which ensures higher cycling safety and stability.2. Using 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, 180, 270 and 360, note any differences in the measured values. Align the derailleur hanger by applying pressure to the tool arm. The results can be checked immediately.3. Good in Design: Comes with 400mm length, the tool enables simple operation, largely simplifying your working and improving efficiency.4. Great Material: Adopting premium aluminium alloy material with a sturdy structure, not easy to deform and very durable for long using.5. Easy Carrying: Light in weight and compact in size as well, the tool can be conveniently carried for both indoor and outdoor work.Specification:Item Type: Derailleur Hanger Alignment GaugeMaterial: Aluminium AlloyLength: Approx. 400mm / 15.75in.Package List:1 x Derailleur Hanger Alignment Gauge3 x Accessory