This is a tank crew face mask, which would have been issued to every member of a tank’s crew to protect his face and particularly his eyes from the effects of ‘splash’.
‘Splash’ was a most unpleasant and unavoidable aspect of tank warfare, bought about when bullets from enemy machine-guns struck the armour plate of the tank. Some of the lead from the bullet, splattered on the outside of the armour, squeezed in through the slightest gaps as microscopic droplets of molten metal, tiny slivers of metal would also come off of the inside of the armour from the impact of bullets on the outside. On exposed flesh it was bad enough, it worked its way under the skin and emerged as tiny black spots, but if any of it got into your eyes it could do untold damage, even to the extent of leaving you blind.
The face mask was supposed to protect you. It was made of metal covered with a thin layer of leather on each side and was held in place by ribbons, that you tied around the back of your head. The mask fitted over your nose, eyes and mouth, and the eyes were protected by thin metal plates with slots cut in them for you to see through while the mouth was covered by a layer of chain mail, hanging from the bottom of the shield and designed so that you could take a swift drink from your water container without having to remove the entire mask.
In practice these masks were not popular. It was hot inside a tank and as your face sweated it was difficult to keep the mask in place. Added to which it was hard enough to breathe anyway, inside a tank, without something pressing on your nose so many crew members chose not to wear them and took the risk of damage from ‘splash’ in their stride.
When tanks first appeared the men were issued with these special leather helmets.
It meant that you could bang your head inside the tank and it didn’t hurt – too much. However there was a problem when you got outside. The helmet was said to look rather like a German infantry helmet and there were instances of tank men being shot at by their own side – so they soon stopped wearing these as well.