Shimano STEPS RT-EM600 disc brake rotors for speed sensor systems provide consistent and powerful braking on rugged mountain bike trails.Using Shimanos Ice Technology, the rotor significantly reduces heat build-up in the brake system to ensure consistent high performance braking even on the steepest downhill stretchesCenter Lock lockring design offers fast and easy installationFor rear only with magnet bracketFor narrow type brake pad onlyRecommended Brake kit: M6000/MT520/MT420Item SpecificationsHub/Disc CompatibilityCenter-LockRotor Size (mm)203