Acros ah 34 ec34 28 upper headsetperfect for updating your existing upper headset interface, this upper headset features a hard wearing aluminium construction. This makes it more than capable of handling all the abuse that's associated with road racing and all day epics on your mtb. Allowing your fork's steerer to rotate inside the frame's headtube, this lower headset is equipped with stainless steel bearings. This gives it an extra layer of durability, while its r3 seal allows it to perform in all weather conditions. Featuresheadset material aluminiumbearing material stainless steelseal material r3 metal reinforced rubberuse road, mtbsteerer diameter 1 1 8headset type conventionalpart number 1602605r5sbuy supacaz components from chain reaction cycles, the world's largest online bike store.