This spacer is made from 6061 billet aluminum, it fits into the fork lug on a YZ and necks it down to 14mm/1.5 thread so that you can thread your front axle into the fork, This spacer is specifically designed to run with our YZ wide clamp set up, it is for the Non brake side. This spacer will work in many other applications and it fits some KX/CRF fork lugs also.