The wireless cardioid microphone with RF band M915 (902 to 928MHz) features polar pattern, 1, 10, 25 or 50mW user selectable RF output. It requires USB or battery power and an internal antenna. Battery status and mute status LED indicators. It features mute on/off button, talk, mute, logic mute, on/off programmable switch. Two rechargeable standard AA size NiMH battery included. 4 hours battery charge time. 8-hour continuous usage per charge, typical @ 1mW battery talk time. Suitable for WS800 digital wireless microphone system.