Cane Creek 40 Series Headset Solutions. Features: 40-Series Solutions: separate top and bottom headset cup assemblies for tapered, reducer and conversion applications (mix & match system helps reduce inventory overlap) Same features and materials as 40-series complete headsets Top assemblies include star nut and top cap, while bottom assemblies include crown race (Carbon indicates a carbon top cover) Cane Creek Integrated 41.0mm ID (36x45), Campy Hiddenset 42.0mm ID (45x45) , ZS (ZeroStack), or EC (traditional, External Cup) available for 1", 1-1/8" and tapered steerers Please see: www.canecreek.com/headset-fit-finder for fit information Specs: S H I S:ZS44/28.6 Upper Lower:upper Stack:8mm Color:black Weight:44g