[High-quality materials]: The bicycle handlebar riser is made of high-quality high-strength aluminum alloy material, and the workmanship is strict and exquisite. The matte process makes the surface more texture. [Adjustable height]: The height of the bicycle rod can be adjusted freely, and 4 shims can be used in various ways. You can adjust the new stem height completely according to your driving requirements. [Safe and stable]: The handlebar is fixed by double screws, making the handlebar more firm and not easy to fall off, and safe use is more assured. [Easy to install]: Just slide the spindle extender onto the steering tube and tighten, it is very easy to assemble. characteristic: Colour: Black. Material: Aluminum alloy. Size: about 12cm x 3.5cm (including lid 12.4cm) Upper size: 2.8cm, inner 2.2cm Lower size: 3.5cm, inner 2.8cm The diameter is 28.6 mm (universal caliber)