Cannondale Reducer Headset - SI/Headshok to 1-1/8" - KP058
Cannondale Integrated Headset - Adapts Headshok Headsets to use with 1 1/8" Fork - KP058
If you are trying to convert a Lefty or Headshok frame to use a standard 1 1/8" fork, this may be what you need. There are a couple different kinds.
This is for frames that take the Headshok headset bearing straight into the frame without the use of cups. Frames that are like this include the Rize/RZ series and some carbon bikes. If you have "System Integration" written on black cups pressed into the frame, this will work, but it presses into those cups increasing the stack height.
Kit includes bearings, crown race, adapters, top bearing wedge, top plate, and optional stack height spacer for the bottom for increased crown clearance with certain forks.