Designed to bridge the gap between the 40-series and the 110-series Internally countroured and relieved to minimize weight and maximize strength Low-friction upper bearing seal completely seals cup from contaminants and is fully captured by the top cover with no loose parts Dual-seal crown race provides excellent seal efficiency with low friction Carbon friendly captured compression ring Premium, sealed stainless-steel Hellbender bearings Interlok spacer cmpatible Bright - dip anodized Attributes Bearing Grade Sealed cartridge Crown Race Diameter 40mm Headset Position Complete Headset Type Integrated Lower Cup 52mm Material 6061-T6 Aluminum Primary Color Black SHIS Lower IS52/40 Stack Height 10 Steerer Tube 1-1/8''-1-1/2''