RAF H-type oxygen mask instruction sheet c. 1946

Approximately 18.5 x 24.5cm.  May 1946.  Three sheets, printed both sides.  Instructions for use and fitting of the H-type mask with details on sizing, adjustment and cleaning.  It also covers the importance of the mask valves and use in very low temperatures.  Illustrated with photographs and diagrams.  Creased/folded with light soiling and corroded staples.  This sheet was issued in the box with all new masks.  Rare to find.  Stock code P18091.