DBX DriveRack RTA-M - measurement microphone for dbx Driverack, Polar Pattern : omni-directional, back electret-Condenser, 20 - 20.000 Hz, Impedance : 250 30% (at 1,000Hz), Sensitivity : -63 dB +-3 dB ( 0 dB=1V/ microbar 1,000 Hz indicated by open circuit ), 9-52 V Phantompower necessary, incl. clamp and case