Due the high number of combinations for upper and lower headsets PRO offers its upper and lower headsets separately. So you can arrange your own individual solution for your frame and fork.
The lower PRO ZS headset with semi-integrated cups comes with high quality double sealed cartridge bearings and anodized aluminum cups.
describes the semi-integrated 1.5" Ahead reduction headset for 1 1/8" steerer. The S.H.I.S. denotation (see attachment) of the lower part offered here is ZS56/30.
Construction type (Ahead/Thread): ahead
Included in delivery: lower headset with crown race, cap, starnut, bolt
Material: aluminum, steel
Weight supplement: headset only - starnut, bolt, cap additional 25g - weighed by Bike24