SRAM Shift/Hydraulic Disc Brake 700 10-Speed Rear Shift Rear Brake 1800mm w Direct Mount Hardware (Rotor & Bracket sold separately) B1SRAM HRD hydraulics improve modulation, with lower hand forces that optimize rider effort. SRAM's HRD is a fully sealed system for reliable performance in all weather conditions and is not compromised by water, mud, sand, grit, etc.