SHIMANO ULTEGRA Di2 Hydraulic Disc Brake Dual Control Lever 2x12 Speed ST-R8170-R Road Riding is more comfortable than ever. This is because the redesigned ULTEGRA ST-R8170 dual control lever features a whole new ergonomic, enhanced brake modulation, and wireless electric shifting. With these three you can focus on your next sprint, next descent, and next conversation with your riding partner. Features Clean Cockpit: Wireless connectivity improves aerodynamics and maintenance Overwhelming ergonomic performance based on pro rider feedback Upward grip improves ergonomic in aero position Optimized brake control Lighter and smoother lever operation Increased modulation by extended brake control Works with both wired and wireless connectivity Available with additional satellite shifters Easy to replace CR1 Uses a 632 battery (battery life: 1.5 to 2 years) Shimano ULTEGRA Hydraulic Disc Brake Caliper BR-R8170 The new ULTEGRA BR-R8170 caliper provides improved modulation, silent braking system, and easier bleeding. Features 10% increased pad clearance to reduce brake noise Easy maintenance bleeding process JKIT is pre-filled with oil and hose attached to the caliper side, greatly improved assembly efficiency. Greatly reduces bleeding and deflation time! Please try JKIT!!