Experience superior control, modulation, and power with the Ultegra Wireless hydraulic Servo Wave disc brake Di2 STI's, designed for all riding conditions. Enjoy effortless and precise gear shifts thanks to Di2 technology, requiring only a light touch. The system offers programmable full and semi-synchronized shifting, allowing you to customize your gear changes for optimal performance. Tactile buttons ensure comfortable shifting, even with cold hands. The drop bar STI features shift buttons conveniently placed for intuitive operation. The Ultegra BR-R8170 Hydraulic Disc brake delivers enhanced modulation, a quieter system, and an easier bleed process. Its wireless connectivity to derailleurs ensures trouble-free gear changes. The levers boast new ergonomics, more precise brake modulation, and wireless electronic shifting for ultimate focus on your ride. Shimano's SERVO WAVE technology provides excellent stopping power with less effort, especially from the hood position. The hydraulic reservoir tank automatically adjusts pad-to-rotor clearance for consistent braking performance as pads wear. Finely tuneable reach adjusters accommodate various hand sizes. Levers use CR1632 batteries with a 1.5-2 year lifespan. The kit includes bled ST-R8170 STI, BR-R8170 flat mount brake calipers with pads, hoses, and mineral oil (rotors and adapters not included).