The MAS2 stop cam is 35mm high and comes with an Allen bolt and T-nut for mounting in the door's C-profile. The stop cam can be increased in height using the MAS-E expansion module. When closed, the roller door rests on stop cams. These protect the rubber profile and/or the internal optosensors from damage. The height of the cam should be selected so that the hollow chamber containing the optosensor is not compressed, but that the sealing chamber fits snugly against the floor.