Shimano STEPS RT-EM600 disc brake rotors for speed sensor systems provide consistent and powerful braking on rugged mountain bike trails.Using Shimano's 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/MT420 Rotor Size (mm) 180 Pad Compatibility All Pad Compounds Rotor Type Two Piece keyword search STEPS Hub/Disc Compatibility Center-Lock