About this item Package 8PCS bike handlebar spacers in 4 sizes 2mm / 3mm / 5mm /10mm 2 PCS each size, provide various combination to adjust height of handlebars to fit your riding style Material: Bicycle headset spacers threadless are made of black anodized aluminum alloy material with smooth surface and exquisite workmanship, eco-friendly, sturdy and durable to use Size Stem spacers road bike inner diameter is 28.6mm 1-1/8″ headset spacer set, compatible with 28.6mm front stem fork of MTB, BMX, mountain bike, road bike etc Feature: Aluminum headset spacer is lightweight and easy to install, resistant to corrosion, more sturdy and durable than carbon fiber headset spacers, fit most of the bicycles Notes: if you go for heavy duty off road ride, you should use aluminum spacers other than carbon spacers, durabale due to automatic cutting, smooth edge, fit most of the road bicycles