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 foryour 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 Fits: BMW G310 GS 40 YEARS GS EDITION 2021 G310GS 2018-2022 G310R 2017-2022