The R785 Di2 Hydraulic STI Lever and Disc Brake Caliper Set marks Shimano's hydraulic disc brake debut, and because the UCI has not yet approved disc brakes at the pro level for which its flagship Dura Ace groupset is intended, the R785 is atop the pack. The R785s feature Shimano's IceTech technology, which results in braking power that is consistent no matter what the conditions. By placing cooling fins in the braking pads, Shimano has found a way to dissipate heat more effectively, allowing the brakes to grab faster and the pads to last longer. In addition, Shimano's disc break system was designed to work with Di2 electronic shifting. In order to hold the fluid reservoir for mineral oil, the front profile of the R785s is higher than previous Ultegra profiles. The R785s also feature reach and stroke adjustments to ensure that your hand position is ideal. Lastly, keep in mind that Shimano's ST R785 Di2 Hydraulic STI Lever and Disc Brake Caliper Set does not include the rotors.