Anti-Gas Fans from WW1 (1910s)

Over 100,000 of these fans were issued to British troops on the Western Front during the First World War. Invented by Mrs Hertha Ayrton, a civilian scientist, they were used to clear the gaseous residue that collected in shell-holes and craters after a gas attack.

https://www.iwm.org.uk/collections/item/object/30028169