This is the most secure handguard fastening system available. It keeps your guards secure at all times. You tap the end of the handlebar, thread the insert in the end of the handlebar with an Allen wrench, then attach the handguards with the supplied bolts. Machined from 6061 aluminum for added strength and light weight. Includes: Inserts. Two 8 mm flat-head bolts for secure bar end handguard installation. Instructions. Fits most aluminum handlebars. Note: NOT for use on Renthal Twinwall or Azonic Double Wall handlebars. Note: Must use 5/8-11 tap which is NOT included.