For intercom and P.A., this is designed especially for mounting to wall outlet boxes. The WM625S has a simple push-to-operate DPDT snap-action switch.

Specifications:
Operating Principal Moving Coil Dynamic
Polar Pattern Omnidirectional
Frequency Response 300Hz – 4KHz
Sensitivity -42dBV (7.9 mV) @ 1 Pa / -38dBV
Impedance 500 ohms / 2500 ohms