The IG-45 integrated headset features an aluminium cap, bearing cover and crown race with super-smooth rolling, precision 45×45 bearings.

Specifications
1"Adapter - For 1" forks to 1 1/8" frames
S.H.I.S. Stem Clamp Diameter: 25.4 Threadless
Crown Race: 26
S.H.I.S Lower: IS42
S.H.I.S Upper: IS42

1 1/8"
S.H.I.S. Stem Clamp Diameter: 28.6 Threadless
Crown Race: 30
S.H.I.S Lower: IS52
Bearing Type: Sealed Cartridge
S.H.I.S Upper: IS42

1.5"
Crown Race: 30
S.H.I.S. Stem Clamp Diameter: 28.6 Threadless
S.H.I.S Lower: IS42
S.H.I.S Upper: IS42
Lower Stack Height: 14.2
Weight: 85
Upper Stack Height: 20.8
Comes with both 1 1/8 - 1.5 and 1.5 crown race