Material: aluminum Caliper Type: hydraulic Mount Type: flat Fluid: mineral oil Compatibility: Shimano 105 The Shimano 105 ST-R7170 Di2 Shift/Brake System features stress-free Di2 shifting in a small, compact size. Its reach adjust technology allows for a customized distance between the handlebar and lever, while a raised hood peak and hood body increase hand support. The dual control lever makes for easy operation, and custom button functions easily change with the E-TUBE app.