rz140 headset? headset confusion?

[akiracornell]

Got an rz140 off ebay thinking it had a standard 1.5 headtube. After some measuring, i believe this is set to have bearings pressed in. System integration. It measures 50.9 by 7mm deep. Is this the standard for headshocks? Or is there another common version. or is this the new standard? Im looking to put a 1 1/8 fork, but im confused to the options. Would somthing like this below work or is this sized for a non integrated HT

Outlet:Problem Solvers Headtube Reducers > Components > Headsets and Spacers > Headsets | Jenson USA Online Bike Shop

Or must i get this which designates for the rz.

Cannondale Reducer Headset - SI/Headshok to 1 1/8 - CannondaleExperts.com

[Prophet Julio]

All the Cannondale mtbs like Rush, Rize, Prophet, Scalpel, Jekyll etc. have the same headsets. The bearing is a B 543 DD. The second choice you listed is probably right.