Item Description40-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 headsetsTop 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 (Zero Stack), or EC (traditional, External Cup) available for 1", 1-1/8" and tapered steerersPlease see: www.canecreek.com/headset-fit-finder for fit informationItem SpecificationsS.H.I.S.: IS42/28.6 carbonupper/lower: upperstack: 9mmcolor: blackweight: 35g: