The Shimano Zee M640 I-Spec-B Disc Brake and Lever Set are a fully bled system that use a performance optimized Servo-Wave systems with full adjustability on the fly. The 4-ceramic pistons in 2 different diameters optimised for heat distribution and stopping prowess. Shimano recommend that you use Ice Tech Centre-Lock rotors for optimum braking performance in a 203 mm diameter. As the set doesn\\\'t come with the rotor or adaptor this gives you the freedom to use what ever you want to use.