This is a clamp designed to level your bed with the help of a dial gauge (see parts list for the gauge i designed the clamp for)
With this clamp you can attach the gauge to your hot-end (single and dual nozzle) and make sure your bed is level by a precision of 0,01mm. The clamp is simply pushed onto the stock hot-end fan.
The raft isn't needed by this design but removing all supports is much easier since they stick to the raft and can be pealed of easily.
TIP: To make sure the clamp is even on the fan, screw in additional two screws (should be spares in the box) into the fan. So the clamp has an even surface to be pushed against.