For intercom and P.A., the WM625S is designed especially for mounting to wall outlet boxes. The WM625S has a simple push-to-operate DPDT snap-action switch. Specification:Operating Principal Moving Coil DynamicPolar Pattern OmnidirectionalFrequency Response 300Hz � 4KHzSensitivity -42dBV (7.9 mV) @ 1 Pa / -38dBVImpedance 500 ohms / 2500 ohms

CAD Astatic Omnidirectional Wall Mount Dynamic Microphone ~ Push-to-Talk