The Verifact Model D is an omni-directional, low impedance, electret condenser microphone with built-in preamp for producing line level output. It provides listening capabilities between the area of coverage and the Louroe Base Station. Microphone assembly is mounted to the back of a stainless steel face plate that fits into a single gang electrical box. Designed for wall or ceiling mounting. Model D microphone is compatible with all Louroe base stations. Single gang electrical box not included.