Shimano Ultegra ST-R8170-LF Di2 Shift/Brake Lever - Left 2x Black. Shimanos 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. Your time on the bike is precious let Shimano make it even better.The wireless connection provides a clean cockpit enhancing the aerodynamic effect and easy maintenanceUnparalleled ergonomics engineering refined with feedback from professional ridersRaised hood peak improves ergonomicsBrake control is optimized with light and smooth lever actionEnhanced modulation thanks to an expanded braking control areaCompatible with wireless or wired connectionHigh electronic energy efficiency with 1.5 to 2 years of battery life from CR1632 shifter batteriesCan be used with additional satellite shifters