STC 4035 Microphone, Ser. No. 219, c.1950.
This microphone replaced the STC 4017-C. It was a reliable omnidirectional microphone used to record and relay speech as well as sound effects in the fifties and sixties.
Like the STC 4017-C that came before it, this microphone is a moving coil type. In moving coil microphones, a coil wire surrounds a magnet and is connected to a diaphragm which vibrates in response to sound waves. When the diaphragm moves in response to sound, the attached coil vibrates back and forth, generating an electrical current, which produces the audio signal.