The 40-Series is the workhorse of Cane Creeks headset line-up. Representing the balance of performance, durability and value, the series incorporates all the features necessary for a robust, lightweight, long-lasting headset. Zero stack uppers press into head tube with very little stack height. Lowers are either zero stack or external cup.Features:Sealed black oxide bearings Carbon-friendy compression ring captured in top cover keeping shims in place Steel crown race with integrated seals Interlok spacer compatibleSpecifications:Defined Color: Black Color: Black Weight: 171 Bearing Type: Cartridge S.H.I.S. Stem Clamp Diameter: 28.6 Threadless Crown Race: 30 Upper Stack Height: 8 S.H.I.S Lower: EC44 S.H.I.S Upper: ZS44 Lower Stack Height: 12