A continuous positive pressure device which includes an air reservoirconnected to a delivery device (e.g. mask or mouthpiece) by an air supplyhose； the reservoir includes a rigid protective housing and a plate whichapplies uniform pressure on the reservoir irrespective of its degree ofinflation； the plate is connected to the housing by a non distorting andexpandable frame which can expand or contract to permit movement of the plateonly in a single plane, as the reservoir inflates or deflates.
