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 steerersItem Specifications: Upper/Lower: Upper, S.H.I.S. Stem Clamp Diameter: ZS56/28.6, Color: Black, Model Name: 40-Series Upper, Weight: 101g, Stack: 8mm,