WW2 British Dog Respirator/Gas Mask

I thought I’d share what is probably the favourite piece in my collection: a Second World War British Dog Gas Mask/Respirator.
Throughout history, man has went to war alongside animals which have often played a pivotal role in having an advantage against the enemy. As a result, in modern history animals have been provided with various means of protection against enemy weapons and other hazards. In the first half of the last centaury gas was one of the most feared weapons due to its large scale use during the First World War, during which its effects were clearly displayed and become very well known. This led to protection against such weapons becoming paramount for any man, or animal that may be at risk of exposure. Development of protective equipment for animals continued throughout the Post WW1 years and well into WW2 which is where this particular piece falls into place.
The exhale valve, eyepieces and the filter mount are identical to those on the standard issue Lightweight Respirator. The facepiece itself however is very different and is made from a series of pieces of sheet rubber, which are secured together with glue. It also features a peripheral face seal inside which is quite similar to the neck seal you would find on a drysuit. Behind the face seal are is another piece of sheet rubber with ear holes which would also cover part of the dogs neck. Connected to this are a series of straps which form a suspension system which secure the mask to the dog, it also incorporate a metal ring which allows a lead to be fitted. The only markings are on the exhale valve, which is stamped "B. W.& M (Barringer, Wallis and Manners Ltd) L2 11/1942" and on the filter, which has been hand painted with "Ptn 1/45 No.151 Wt:8 1/2 Ozs." I’m not too sure of when exactly it dates from, but it is certainly no earlier than the date found on the exhale valve. The filter marking 1/45 could perhaps mean January 1945, however a positive confirmation on this is unfortunately impossible.
Here are some detailed photographs of the respirator.
I know this is the second time this exact mask has been shown on this forum, but I thought it was worth sharing a second time round
Thanks again to Dean O (CampX) for the opportunity to own such a fantastic piece.
Regards,
Danny