1. Material: Aluminum Alloy
2. Expand the flywheel speed change more smoothly.
3. Five colors available, give your mountain bike a little individuation.
4. Aluminum alloy material, CNC workmanship, solid and firm, very durable.
5. Great accessory for cycling enthusiasts.
6. Used for rear derailleur extension, apply mountain freewheel 40T / 42T / 46T / 50T, or 32T / 36T Road flywheel.