Ritchey Logic External Cups EC Headset:

The Ritchey External Cup EC Threadless headset features a smaller upper bearing to save weight, while the oversize lower bearing is designed to handle loads. Deep bearing cups promise solid insertion.

Material: steel/plastic
Threadless
Stack height: 28.9mm
Stack height upper: 15.7mm
Stack height lower: 13.2mm
Headtube ID: 34mm
S.H.I.S. upper: EC34/28.6 (1 ?”)
S.H.I.S. lower: EC34/30 (1 ?”)
Bearings: retainer ball-bearing
Top cap included
Weight: 156g
Colour: black