Check the listing for details. Wolf Tooth Premium IS Headset - 6061 Aluminum, Sealed Bearings, 7mm Stack, Black. Condition: New. Listed at 70.85 USD. 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 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. Compatibility Any frame that uses IS (Integrated Standard) headsets with 41mm upper and 52mm lower outer bearing diameter. Uppers and lowers sold separately. Enduro stainless steel sealed bearings included on both the upper and lower. IS42 is not compatible with Specialized mountain bikes or bikes using.