This item appears to be a dual air horn, manufacturing year unknown. According to the maker’s website:

“They generate sound by means of a vibrating diaphragm that modulates the flow of compressed air into a resonating projector. All horn shapes are mathematically calculated to amplify sound while closely retaining its fundamental frequency and natural harmonics.

These horns can be used for indoor/outdoor applications and are ideal for hazardous location use. Volume is adjustable by regulating air pressure.

Typical applications include emergency signaling applications in mines, refineries and industrial facilities. Ideal for individual equipment and plant warnings.”

Find an almost 150 year timeline of the Edwards Signals company history on their website: Edwards-Signals.com