SGC-598 Photography Interview Shotgun MIC Microphone for Nikon Canon DSLR Camera (Need 3.5mm Interface) Low power indicator Transducer Principle: Back Electret Condenser Directivity Characteristic: Cardioid Powered by 1.5V AA alkaline battery Sensitivity: -32dB+/-3dB(0dB=1V/Pa at 1kHz)