Used on the first DH-100 Vampires delivered to Switzerland in 1946, it is of the same design as the helmets worn by the Royal Air Force pilots during World War II, with some minor modifications.
The pictured helmet has been modified with the adjustable central fabric strap that sustained the Huggenberger three strap oxygen masks used with the "Munerelle" system on Morane D-3801 aircraft.
The pictured C-type is fitted with an A-13 A oxygen mask and
The C-Type was phased out (as were the "Stoffhauben"), with the introduction of ejection seats.
Type A-13 A pressure demand oxygen mask:
The A-13 A has the same configuration as the A-13 with few additional changes incorporated, as the addition of a pull the dot snap fastener to the nose strap (the pull the dot was added to the left side of the strap cross-piece, for quick attachment adjustments), the substitution of OD or sage green colored nylon straps for the original black or OD colored cotton straps, substitution of sturdier (redesigned) upper and lower buckles for mask strap attachment, and perhaps most importantly, the use of the new A-2 (later to be known as the MC-3) bailout quick-release connector at the distal end of the oxygen supply hose in place of the original "T-piece" bailout bottle connector (between mask body and hose).
These changes were incorporated into the mask shortly before the improved A-13 A mask was redesignated the MS22001 mask (early 50s).
The A-13 A can be used as the A-14, by dilution on demand.
In this case, both inlet check valves are removed and the pressure-compensated exhalation valve is replaced by a model as the one fitted to the A-14.
This option is to be seen, depending on aitcraft in use, in many
A-13 A and MS22001 used by the Swiss AF.