<!--ProdInc[180021796]/Mall:[reioutlet_US]-->This J-Kit is a complete, pre-bled set with front (left) Ultegra ST-R8170 Di2 dual-control lever, BR-R8170 hydraulic disc brake caliper, hydraulic hoses and fittings Ultegra ST-R8170 brake lever brings enhanced modulation and optimized brake control to every ride by employing Shimano SERVO-WAVE technology The Di2 platform\u2014used on both Dura-Ace and Ultegra\u2014untethers the shifters while delivering fast, reliable wireless shifting Wireless connection provides a clean cockpit, enhances the aerodynamic effect and offers easy maintenance; plus the shifting is customizable via the Shimano E-Tube Project app High electronic energy efficiency means you get 1.5 to 2 years of battery life with the easy-to-change CR1632 shifter batteries (included) Raised hood peak improves lever ergonomics; ergonomic engineering has been refined with feedback from pro cyclists Lever offers light, smooth action and is compatible with wireless or wired connection Ultegra BR-R8170 disc brake caliper brings a new level of control to road cycling with enhanced modulation and a quicker initial braking point Despite its smaller construction, the caliper system is quieter than ever and easier to maintain 10% wider pad clearance decreases brake noise, and the expanded braking control area offers enhanced modulation Maintenance-friendly bleeding process