About this item Made of high-quality aluminum alloy, precision machined and cut, with a smooth surface, high strength, and corrosion resistance. Used to increase the height of the handlebars, compatible with various mountain bikes, off-road vehicles, mountain bikes, and road bikes. The inner diameter is approximately 25.4mm/1 “, the outer diameter is 30.5mm/1.2”, and the height is divided into 10mm and 5mm. Easy to install, you can add washers of different heights according to your own needs to adjust the handlebars to the most suitable height. There are 10 pieces in one package, 5 pieces each with a height of 10mm and 5mm.