The Shure Model 577B Microphone is a handheld dynamic microphone designed for communications and paging applications that require highly intelligible, low noise output. It can be used in all types of mobile communications, from amateur radio to helicopter news and traffic reports. It is also suitable for public address and paging systems in noisy areas such as factories, airport terminals, and restaurants.

The 577B microphone represents a significant improvement over most microphones with anti-noise features. Shaped frequency response, directionality, and distant sound discrimination contribute to total noise reduction. The microphone operates on the pressure-gradient principle and has two sound entry ports spaced a small distance apart.

The modular design of the 577B microphone greatly facilitates field servicing. The cartridge, switch, and cable can be replaced in a matter of minutes, if necessary.

The 577B is built to withstand mechanical shocks, vibration, high temperatures, and humidity. The exclusive ARMO-DUR® case is impervious to oil, grease, fumes, salt spray, sun, and corrosion. The "Million-Cycle" press-to-talk switch ensures years of reliable service.