From verso of card: "This is the respirator designed for the fighting services. It will also be used by members of those civil Air Raid Precautions services who might have strenuous duties to perform in heavy gas concentrations. This respirator gives the same protection as the Civilian Respirator . . . but for a longer period. It is designed so that the weight of the container portion is carried in the haversack on the chest, and the special face-piece allows heavy and accurate work to be performed without difficulty. The eye-pieces, which are made of splinterless glass, can be unscrewed when the face-piece is decontaminated by boiling."