MTX solid rotors are constructed using one complete segment of Japanese SUS 420 stainless steel, then heat-treated to HRC 36+-2. Lightening and drill hole patterns are as per OEM designs to improve braking performance and reduce the temperature of the rotor. MTX Rotors provide amazing braking control foryour motorcycle. All MTX rotors are designed and manufactured with world-leading, cutting edge technologies: Precision CNC machined and laser-cut technology Japanese SUS 420 Stainless Steel Replacement for Original Equipment OEM Design; lightening & drill hole patterns Specifications: O.D: 240mm I.D: 118mm Minimum Thickness: 2.5mm Rotor Position: Front Fits: Honda CR125R 1990-1991 CR250R 1990-1991 CR500R 1990-1991