Handlebar shims let you easily fit your 25.4 mm or 26.0 mm handlebar into the 31.8 mm clamp of the ShockStop Suspension Stem. Just place the shims on either side of your handlebar and clamp securely into the stem. Once installed, the shims are essentially invisible.Adapts 25.4 mm or 26.0 mm handlebars to 31.8 mm ShockStop Stem clamp.