Abstract: A depth gauge from which lesser depths can be read off accurately on a scale which is expanded in the lower range. The expanded scale is achieved in that the component exposed to the pressure of the water is composed of at least two subcomponents, such as diaphragms or Bourdon tubes, which are subjected in succession to the effect of the water pressure.

Abstract: A pressure regulator for divers' breathing apparatus having a diaphragm case and a diaphragm disposed therein. As a function of the pressure which exists in a space delimited by the diaphragm and which is varied by the diver's breathing, the diaphragm controls, via a control member, a valve having a fixed portion and a movable portion. A pressure chamber is provided in which a reduction in pressure is produced through a channel opening out into the flow of gaseous mixture into the valve at right angles to the direction of that flow. The opening of the valve is assisted and accelerated by this reduction in pressure in order to facilitate the diver's breathing.