Shimano rs685 hydraulic disc brake and mechanical caliper set the new rs685 shifters sit outside shimanos branded groupsets dura ace ultegra 105 etc just as the di2 enabled r785 hydraulic shifters do and feature subdued graphics and design intended to fit in well with any of shimanos road groups provides efficient braking in all conditions oversized 22mm ceramic pistons optimized for heat insulation lightweight and stiffness opposed 2 piston design reduces leading effect and optimal pa