AS3 PERFORMANCE STEERING STEM NUT to fit KTM 125 200 250 300 350 450 500 SX SX-F EXC EXC-F XC 2000-2018. AS3 Performance Aluminium Steering Stem Nut for. They are CNC machined from billet aluminium for a precise fit and have a polished anodised finish which looks great when installed on the bike.