Designed for paging calls and general announcements, the PM-660D desk-top microphone comes with a large talk switch and a lock lever for easy and convenient operation. Rated Impedance: 600 ?, Balanced. Rated Sensitivity: -58 dB (1 kHz, 0 dB=1 V/Pa). Frequency Response: 100 Hz - 10 kHz. It's equipped with a remote control switch (interlocked with the talk switch) for amplifier power on/off operation or chime activation. Output: 4-conductor (2-shielded) cable (2.5 m (8.2 ft)) with 5-pin DIN plug. Dimensions: 100 x 215 x 150 mm.