MTX solid discs 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 disc. MTX Discs provide amazing braking control for your motorcycle. All MTX discs 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: 245mm I.D: 115mm Minimum Thickness: 3.5mm Disc Position: Rear Fits: Yamaha WR200 1998 WR250F 2001 WR250Z 1998-2002 WR400F 1999-2001 WR426F 2001 YZ125 1998-2001 YZ250F 2001 YZ400F 1999 YZ426F 2000-2001