It is a simple, single-button carbon microphone that was held to the pilot's or observer's chest with a pair of straps to allow hands-free operation.  The shorter strap went around the neck, and the longer strap went under the arms.  The angle of the support arm could be adjusted to position the element directly in front of the operator's mouth.

A trace of an insignia remains on the back of the microphone housing, but I have not been able to identify it.  Note the 1913 patent date.

These microphones were widely available on the surplus market for quite some time after the end of WW-1, as seen in this 1930 advertisement.