The 10mm thick clamp of which there are two in each runaround door. This has now changed shape but still fits the Mark 1-3 doors.
From September 28th 2015 the door changed to Mark 4 so the clamps also changed. Be sure to choose the right spare clamps to fit your door.
Any doors previous to this will fit Mark 3 parts and the change of shape does not affect the fit.