Gas Mask and Respirator Wiki

The Ajax F2 was a French licensed copy of the Italian T.33. This mask was used by civilians before the Second World War.

Mask overview[]

The mask is composed of the following parts:

The faceblank, made of moulded rubber, has the following parts attached to it:

  • the housing for the exhale valve
  • the threaded inlet piece
  • the eyepieces
  • the straps

The inlet piece allows the filter to be threaded in. Unlike the T.33, most of the times there is no inlet valve, as it's present in the filter. Only the earliest pieces have an inlet valve, using the same assembly of the Ajax F1.

The exhale valve allows exhaled air to go outside and prevents poisoned air to get in. It's made of rubber, it opens under the light pressure of exhaling and closes hermetically under the negative pressure produced by the inhalation. It can be easily inspected and possibly replaced by unscrewing the lid of its housing. The exhale valve is identical to the one of the T.33 and fully interchangeable.

The eyepieces are made of "Triplex" glass, which itself is composed of two glass layers and a thin sheet of cellulose. This kind of glass prevents poisoned air to get into the mask even after being hit, as only the outside layer of glass would be shattered and the other two layers would maintain the seal. The glasses are affixed to the mask through aluminium frames. Another cellulose lens is inserted in each socket; it's covered in a special material that helps to prevent fogging.

The 5-strap system on this mask is almost identical to the hook system of the T.33, with one frontal strap, two elastic straps at the temples and two hooked elastic straps at the cheeks.

The marking on the left side usually shows just the size (I to IV) and the text "AJAX" is printed above it, occasionally the full name and size both with the roman number and the French size system.


The Ajax F2 came with a civilian filter, a metal or cardboard tube carrier and occasionally some instructions. The filter could be of many different types, all with a 42 mm thread and an inlet valve at the top.

Extra Gallery[]