A Morse Code practice buzzer from the 1940s.   This type of buzzer would have been used by students at a Royal Canadian Air Force Wireless School in World War II.   This one was manufactured by the Wilson Company of Toronto, Ontario, Canada.   An instruction sheet is glued to the underside of the buzzer and stamped "Approved For Gov't Use".   The wristwatch in the photo is there simply to provide a clue to the size of the device.  Buzzer courtesy of the Hammond Museum of Radio, Guelph, Ontario, Canada.
<a href="//commons.wikimedia.org/wiki/User:SteveTheAirman" title="User:SteveTheAirman">J. S. Bond</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>