Wolf Tooth Performance Headset - EC34/28.6 Upper 16mm Stack Ultraviolet PurpleWolf Tooth Performance Headsets are machined out of aircraft grade aluminum and assembled with Black Oxide Cartridge Bearings balancing quality and price. Black Oxide Bearings are made from chromium steel for high load capacity durability and corrision resistance Ultralight stem cap with integrated spacer plus an aluminum bolt and a star nut 5mm top cover = 16mm total stack O ring seal prevents water intrusion around the steerer tube Custom molded