The Sony ECM-77B is a miniature omnidirectional lavalier microphone designed for professional broadcast, sound reinforcement, and recording applications. The condenser element features a miniature profile allowing it to be easily concealed in performance and broadcast situations. The omnidirectional pattern provides even frequency and sensitivity response at the direct and off-axis sections of the microphone capsule.

The ECM-77 provides a wide frequency response of 40 Hz to 20 kHz. The wide frequency response enables the microphone to accurately reproduce audio signal from a wide variety of sources. The ECM-77B is powered with an external 48V phantom power source or AA alkaline battery. The ECM-77B is manufactured with a variety of connectors to accommodate various input devices, this version features a standard 3-pin XLR male connection.