Ritchey WCS Carbon Zero Headset.CX design has a pivoting housing stop for easier cable routing and low friction12.4mm top capFull carbon conical bearing cover, carbon top capStainless steel angular contact bearing packed w/ Ritchey greaseCampagnolo-compatible head tube integrated style, fits 42mm ID head tubes45/45 degree angular contact bearings fit directly into head tubeDesigned for 46mm OD head tubeItem SpecificationsColorBlackWeight93gMaterialCarbon/AluminumSteerer Tube1-1/8" ThreadlessCrown Race30.0Stack Height16.8mmBearing TypeAngular ContactHeadset TypeInternal/44.0mm OD cup/1-1/8" (Zero Stack)Defined ColorBlackS.H.I.S UpperZS44,28.6S.H.I.S LowerZS44S.H.I.S. Clamp Diameter28.6