To the delight of riders and mechanics alike, the new Ultegra BR-R8170 Hydraulic Disc brake delivers enhanced modulation, a quieter brake system and an easier than ever bleed process.High performance Ultegra Wireless hydraulic Servo Wave disc brake Di2 STI's give you control, modulation and power with minimal effort in all riding conditionsWireless connectivity to the front and rear derailleurs for effortless trouble free gear shiftsWith Di2 technology shifting is easy and precise - just a light touch, as soft as a mouse click, is sufficient for the front or rear derailleur to instantaneously select the correct gearFull and semi synchronized shifting programable, Synchro shift compatible meaning a single shifter can control both front and rear shifting which can be fully custom tuned to your riding preferences. Semi synchronized shifting means when a front shift is made the rear mech will automatically correct to the appropriate ratioSimply pressing tactile buttons allows effortless an