I received this information from techsupport at Chris King:


The Cyclus headset press uses a CKpress adapter with an ID (inside diameter) of 16mm. They have Cyclusspecific headset press adapters available and you can order themdirectly from CK at 1.800.523.6008 or you can order them through yourlocal bike shop.


The ID of various headset types are asfollows:


22.1mm ID = Park
20.1mm ID = VAR, Woodman, Hozan
18.1mm ID = Pedros, Campy, ICE, Nashbar
16mm ID = Cyclus, Bicycle Research


Also, the adapters are marked with A,B, C, and D. The code is as follows:


A = Park
B = VAR, Woodman, Hozan
C = Pedros,Campy, ICE, Nashbar
D = Cyclus, Bicycle Research