FSA Orbit X Threadless Headset 1" H2086 6.1mm/31.5mm Stack HeightFSAs core line of headsets that have become an industry benchmark\nAll Orbit headsets feature forged and CNC machined 6061 T6 alloy cups Orbit IS, CF, Z, ZS, X, MX, XL II include angular contact bearings Orbit Xtreme Pro include stainless steel industrial cartridge bearings and stainless crown race Orbit UF include lower angular contact bearing and upper 5 32 inch caged bearing Orbit DL include 5 32 inch caged bearings IS: 36x45 degree Cane Creek