Wolf Tooth Premium headsets are machined out of aircraft grade aluminum and feature high-end bearings made by Enduro. They are engineered to use the largest possible ball size and are filled with high-pressure waterproof lubricant. A pair of dual-lip seals ride in micro-grooves to keep out water and debris.Uppers and lowers sold together as a setEnduro stainless steel sealed bearings and O-ring seals prevents water intrusion around steerer tube included on both the upper and lower systemUltralight stem cap with integrated spacer plus an aluminum bolt and a star nut, 6 mm stack height top cover onlyLifetime warrantyItem SpecificationsBearing TypeCartridgeColorOliveCrown Race40Defined ColorGreenMaterialAlloyS.H.I.S LowerEC34S.H.I.S UpperEC34S.H.I.S. Stem Clamp Diameter28.6 ThreadlessUpper Stack Height6 Wolf Tooth Premium Headset Headsets UPC: 810006808476