König's Smoke Helmet - the first widely used firefighting respirator in Germany, 19th Century

The water shower is optional. The important part of this is the firefighter on the right of the picture who operates the bellows to provide fresh air for the one wearing the mask.

The König's helmet was very successful with about 6000 units sold and his company still fire fighting equipment and uses that helmet in the company logo.

[Info and description courtesy of /u/Sigeberht of Reddit]