Dimension 25.4 Stems are fully forged 6061-T6 aluminum stems that have a 4-bolt handlebar clamp. ?FEATURES: 2-D forged AL-6061-T6 Four-bolt handlebar clamp 41mm height Dimension stems are not intended for use with carbon handlebars or carbon steerer tubes SPECS: Material: Alloy S.H.I.S. Stem Clamp Diameter: 28.6mm Bar Clamp Diameter: 25.4mm Stack Height: 41mm