Aheadset Sealed Top Cup and Bearing 1 1/8 threadless
Got this on a bike with mismatched headset. Of the 8 or so pieces of a headset, these two seem to go together:
a) Black alloy top headset cup for standard 1 1/8" threadless steer tubes
b) Sealed angle cartridge bearing ACB - this looks to be 45* Campy standard - Spins nicely
You would still need the compression ring with beveled mating edge -and the dust cap, etc... Maybe you have a broken or incomplete Headset at home to complete
If you have an Integrated headset that you'd like to use on a standard bike, you could use this cup with those parts.