Cycling BMX Bike MTB Bike Track Bike Fixie Fixed Gear Bike Single Speed Bike Threadless Headset 1-1/8" - Red Lightweight and easy to install Stack height(mm): 17.5 + 12.5 = 30 Diameter(mm): 28.6(1 1/8") internal headsets;Made of 6061AL-T6 full fet CNC machined Inner head tube diameter(mm): 34 x 30;Weight: 110g/set Bearings : 2 sealed cartridge brarings;Suitable for road bikes, BMX bikes, mountain bikes, fixies bikes, track bikes, single speed bikes etc