WWII USAAF T-30 M Throat Mike.
The T-30 throat microphone was the most commonly used tank microphone and standard of the US Army Air Forces in WWII. This carbon microphone was strapped around the wearer's neck, with the two 1-inch round pickups made of black rubber contacting the wearer's throat near his Adam's apple. It is anchored around the wearer's neck by an elastic strap. These pickups transmitted sound vibrations as the wearer spoke, and allowed voices to be heard over the background tank and battle noises. The T-30 microphone had a small two-pronged PL-291 plug, which was connected to a JK-48 jack on a SW-141 push-to-talk switch.
It was produced in over twenty variations by different manufacturers, those being indicated by a suffix code letter to the type designation. In this cast the letter M indicates this particular unit was made by the Universal Microphone Company.
The strap on this unit is in good condition as is the rubber and the unit could be worn by a re enactor