Wolf Tooth headsets are machined in the USA with aircraft-grade 6061 aluminum. 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 EC headsets are for frames with external bearing cups, which places the bearing outside of the frame with these headsets. Premium Headsets with Enduro stainless steel bearings have a lifetime warranty. Upper assembly features: - Ultralight Stem Cap With Integrated Spacer plus an aluminum bolt and a star nut. - 5mm cover = 16mm total stack, 15mm cover = 25mm total stack, 25mm cover = 35mm total stack. - O-ring seal prevents water intrusion around the steerer tube. - Custom-molded upper lip seal provides additional protection for upper bearing.