Rear Derailleur Hangers X4S HydraPak bladder: Leak-proof

HydraPak bladder: Leak-proof

Four-way stretch perforated neoprene cuff provides support

BUILT FOR MX & TRAIL: Lightweight

and woods riding with superior element resistance

Clear business card sleeve and adjustable shoulder strap add travel-ready utility for racers or crews

Rear Derailleur Hangers X4S HydraPak bladder: Leak-proofThis part is what attaches your derailleur (the component that allows you to shift gears) to your bike frame. In the case of a crash the derailleur hanger is designed to fail before causing damage to the bike frame or the derailleur. It is a good idea to have a spare derailleur hanger handy. Note: the derailleur hanger is specific to your model of bike