Crystal Microphone Mounted in a Plastic Box

A multi-purpose electret condenser type microphone, mounted in a plastic case with two 4mm output sockets, an on/off switch and power indicator. Can be used for various applications and experiments requiring an audio input, including voice and music waveforms, by connecting it directly to an oscilloscope and setting the voltage to 5mV/div and timebase to 2.5ms/div. The microphone has an output impedance of 2.2Kohm and comes supplied with a PP3 type 9V battery.
Dimensions: 68 x 120 x 36mm. Sensitivity: -42dbFrequency. Response: 20Hz to 20kHzOutput Impedance: 2.2kohm.