Wolf Tooth headsets are machined here in our Minnesota shop with aircraft-grade 6061 aluminum. They are designed to be lightweight, strong, and durable. Our headsets have three levels of industry-leading custom sealing to protect bearings from the elements and prolong the life of the headset. Available in a variety of colors. These ZS headsets are for frames with internal bearing cups that are pressed into the frame. Premium Headsets with Enduro stainless steel bearings have a lifetime warranty. Lower assembly features: - Custom-molded dual-lip seal on the crown race protects lower bearing in the toughest conditions. - All components are precision machined in-house at Wolf Tooth from aircraft-grade aluminum to ensure the highest level of quality. - Service and additional parts available.