Bicycle Fork Stem Extender Bike Handlebar Riser Head Up Adapter (Black) Material:Aluminium alloy Base diameter: 1-1/8" (28.6mm)(approx) Fork stem diameter: 28.6mm (standard)(approx) Stem height:3pcs x 0.5cm, 1pcs x 1cm Suitable for mountain bicycle to rise up the handlebar fork stem