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. Lower assembly features: - Custom molded dual-lip seal on the crown race to protect the lower bearing in the toughest conditions. - 12.25mm stack. - Service and additional parts available.