MI-8100 is a shotgun type directional microphone which sharply catches the intended sound. This directional microphone is helpful for the removal of background noise in the simple sound source exploration and in abnormal sound detection. Flat frequency characteristic from 50 Hz to 20 kHz and sharp detection with high S/N ratio provide high sensitive detection of various sound coming from the specific direction. By combining the acoustic vibration monitor BL-1100, only the intended frequency or sound is focused and caught clearer.