The 210 Surveillance Mic from CAD Astatic of Solon, Ohio, is a commercial-grade, omnidirectional, button-style model with adjustable line-level and internal audio limiter. The miniature-boundary microphone is designed for installation in security, ambient monitoring, and observation applications. The visually unobtrusive microphone offers a variable output level to effectively interface with security cameras, digital video recorders, and other observation and recording devices. The internal audio limiter circuitry improves intelligibility by protecting the audio signal from distorting sensitive recording circuitry in cameras and recorders. The volume control is protected from tampering. The microphone’s all-metal, threaded housing is designed for commercial applications and allows it to be installed in ceilings, walls, tables, and other surfaces.