The SRAM Guide R (B1) Disc Brake features SRAM's new S4 caliper with Bleeding Edge design that updates the fluid and bleed routing for easier brake maintenance, with a bleed adapter plug that seals off the system from air and dust. The new caliper also boasts SRAM's Heat Shield technology, which consists of stainless steel shields that buffer the connection between the pad and caliper body to reduce head transfer to the hydraulic fluid and reduce its temperature by a claimed 20-degrees Celcius under heavy use.The Guide R brake also utilizes a Timing Port Closure, with its sliding cup seal and port mechanism. This system provides immediate actuation with the DirectLink lever, which also facilitates fantastic one-finger modulation. Moreover, the DirectLink lever features tool-free Reach Adjust for quickly personalizing your set-up.Note that the Guide R Disc Brake comes in either front/left or rear/right variants, with included lever and caliper configuration. It's compatible with SRAM's Centerline Rotors (sold separately) and uses DOT 5. 1 fluid. Additionally, the Guide R is Matchmaker compatible, meaning you can run multiple controls off one lever clamp for a more streamlined set-up.