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: Harley Davidson FXDBI DYNA STREET BOB 2006-2018 FXDC DYNA SUPER GLIDE CUSTOM 2000-2012 FXDF DYNA FAT BOB 2000-2017 FXDWG DYNA WIDE GLIDE 2007-2015