Wolf Tooth headsets are machined in the USA with aircraft-grade 6061 aluminum. Our Performance Headsets are built with Enduro black oxide bearings and have a one-year warranty. Our headsets have three levels of superior custom sealing to protect bearings from the elements and prolong the life of the headset. They are designed to be lightweight, strong, and durable. Available in a variety of colors. These IS headsets are for frames with molded-in internal bearing cups. Upper assembly features: - Ultralight Stem Cap With Integrated Spacer plus an aluminum bolt and a star nut. - 7mm top cover = 8mm total stack. - O-ring seal prevents water intrusion around the steerer tube. - Custom-molded upper lip seal provides additional protection for the upper bearing. - Bearing top cap outer diameter 45.8 mm