Rear mounted hydration system holds two bottles and attaches directly to the seatpost for easy hydration on the go. Features: Full angular adjustment allows bottles to be rotated Brackets included to mount two Co2 cartridges Fits 31.6mm to 27.2mm seatpost with shims (included) Includes two cages and 6061-T6 Aluminum clamp and extension Specifications: Mount: Seatpost Material: Plastic/Composite Application: - Color: Black Weight: 228g