(Matches David Clark M-4 or equivalent) This mic has noise reduction ratio: 10 to 1, up to 1 KZ. Hermetically sealed. Amp: 1X10-3. Front to back ratio. Color: black
This Electret Microphone is a noise canceling type designed to operate in place of carbon and amplified dynamic microphones. It will not operate in circuits that do not supply a DC bias voltage.