These are 3in tall extensions for your risers or bolt on handlebars. Snap this extension on to a 1/2in drive socket wrench to tighten the extension to any riser or direct bolt on handle bar with 1/2-13 NC threads. All Pangea bolt on bars and most HD compatible risers are 1/2-13NC threads but you will want to confirm your thread size before ordering. machined out of steel and dipped in brilliant chrome. base diameter is 1 3/8in diameter.