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. These IS headsets are for frames with molded-in internal bearing cups. Premium Headsets with Enduro stainless steel bearings have a lifetime warranty on the bearings.