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. Compatibility Any frame that uses IS (Integrated Standard) headsets with 52mm lower outer bearing diameter Uppers and Lowers sold separately Enduro stainless steel sealed bearings included For the guide to determine which headset you need, click here. Tech Specs Lower Assembly Enduro stainless steel sealed bearings Custom molded dual lip seal on the crown race to protect lower bearing in the toughest conditions All components precision machined in-house at Wolf Tooth from aircraft grade aluminum to ensure the highest level of quality