The Shimano Ultegra Di2 rear disc brake set pairs the ST-R8170 right shift/brake lever with a BR-R8170 flat-mount hydraulic caliper.

• Right ST-R8170 Di2 lever with rear BR-R8170 caliper, pre-filled with mineral oil
• Wireless 2x12-speed Di2 shifting; lever runs on a replaceable CR1632 coin cell
• Flat-mount two-piston caliper with One-Way Bleeding
• 10% more pad clearance than the previous model to reduce rotor rub
• Finned resin (Ice-Tech) pads included
• Servo Wave lever with reach adjustment; 1700 mm hose