40-Series Zero Stack headsets set the standard for performance, durability and value. Drawing from the premium 110-Series design, the 40-Series includes all the features necessary for a durable, lightweight, long-lasting headset. FEATURES: Sealed ZN40 cartridge bearings 6000 series alloy cups and materials Steel crown race with integrated seals Interlok spacer compatible Compatible with tapered 1-1/8" to 1-1/2" steerer tubes, or straight 1-1/8" steerers with a conversion crown race (sold separately) SPECS: Color: Black S.H.I.S. Stem Clamp Diameter: 28.6 Threadless Crown Race: 40 S.H.I.S Lower: ZS56 Bearing Type: Cartridge S.H.I.S Upper: ZS44 Defined Color: Black Lower Stack Height: 4 Upper Stack Height: 8 Weight: 89