Q3 professional stereo microphone the product using the nikon external stereo microphone ME 1 product design the use of MS (Mid - side) stereo sound pickup system can pick up the natural sound transmit ultra clear stereo sound quality can also according to the sound source location set up sound pickup pattern (affect sound field width) to 90o or 120o and is applied to the users of SLR cameras specially equipped with damping system thus inhibiting such as noise because of the automatic focus. Feature: frequency response 30-18000Hz sensitivity: -40dB(0dB=1V/Pa at1KHz)?. Pointing to the characteristics of single directivity x 2. output impedance: 200ohm. SNR: 76dB(1KHz at 1Pa).? The loudest level: 120db(at1KHz harmonic distortion< / =1% ). Power supply: DC 3V. Type: MS(Mid-Side) stereo system. Power supply: DC 3V battery. Battery lief: 800 hours(included). Pickup pattern?: 90o or 120o 2 level switching.