Shimano Ultegra ST-R8170A Di2 Shift/Brake Lever with BR-R8170 Hydraulic Disc Brake Caliper - Left/Front 2x Flat Mount Black. Your time on the bike is precious let Shimano make it even better. Ultegra ST-R8170 brake levers bring enhanced modulation and control to every ride by employing Shimanos proven SERVO-WAVE technology. The Di2 platform untethers the shifters while delivering fast and reliable wireless shifting. The BR-R8170 hydraulic 2-piston disc brake caliper brings a new level of control to the road cycling world with improved modulation and a quicker initial braking point. Despite its smaller construction the system is quieter than ever and easier to maintain.The wireless connection provides a clean cockpit enhancing the aerodynamic effect and easy maintenanceWider pad clearance decreases brake noiseMaintenance-friendly bleeding processUnparalelled ergonomic features such as raised hood peaks on leversBrake control is optimized with light and smooth lever actionEnhanced modulation thanks to an expanded braking control areaCompatible with wireless or wired connection.