This is an unusual one. These were used at the turn of the century as a tool for firefighters to blow smoke out of the way as they entered and traveled through the area on fire. Made by the Siebe Gorman Company who alson made the first scuba diving suit (the kind with the big metal round helmet). They also used a similar device that was operated by foot to supply air to the divers via a tube that connected to the helmet. Purchased this one blind at a thrift store for $150 and sold it for..........$150.