WWI era Small Box Respirator with bag. Named too!

Yard sale find from last week (with the help of craigslist, haha). I've been on the hunt for WWI stuff like this since I picked up the uniform (just posted). There is something special about WWI, it might just be how under appreciated it is today.

This is an English mask design that was adopted by the Americans before entering into the conflict. It had been proven to be particularly effective, so we didn't bother trying to fix what wasn't broke.

The lenses are very clear (it's surprising actually), but the rubber hose has hardened like one would expect 90 year old rubber to do. There is also a small separation where the hose connects to the mask, but it's an easy patch job. I've tried it on and it's really not the worst mask I've tried.

It is meant to be worn with the bag (and canister) slung over the head on the chest, like in the 4th image.

Also, no equipment category in military and wartime? (rabble rabble rabble!!!)