MTX floating discs are made from two segments of stainless steel which are riveted together to allow the outer section of stainless steel to expand under extreme temperatures. The outer section is manufactured from Japanese SUS 420 stainless steel then heat-treated to HRC 36+-2 while the centre of the disc is manufactured from steel or alloy. Fits: Kawasaki KX250F 2015-2019 KX250X 2021-2022 KX450F 2015-2019 KX450X 2021-2022