●Compatibility: This bicycle rear hook is compatible with Trek Gary Fisher. ●Model: 322175/318610, please confirm before ordering. ●Material: made of aluminium alloy, sturdy and durable, suitable for long-term use. ●Function: used to replace or upgrade the front derailleur hook of your bike and protects your bike from damage when dropped. ●Package: includes 1 x bicycle rear hook, 2 x screws.