Ritchey:

The Ritchey Comp Cartridge Integrated IS 1.5″ headset features sealed cartridge bearings and is designed for bicycle frames with 1.5-inch upper and lower headtube dimensions and forks with tapered (1-1/8-~1.5″) steerers.

Material: alloy
Stack height: 10.8mm
Headtube ID: 52mm
Headtube OD: 56mm
S.H.I.S.: IS52/28.6 (1.5)
Bearings: 51.80/40mm 45/45 – sealed cartridge (ACB)
Top cap NOT included
Weight: 112g
Colour: black