Philips EL-6020 Dynamic Microphone

The EL-6020 from Philips appeared in 1954 as an extremely expensive microphone for professional use. 

Omnidirectional electrodynamic microphone especially suitable for high quality sound installations, broadcasting and sound recording. Resistant to humidity, sea air corrosion and temperatures up to 60º C, as well as most chemical and industrial vapours. These characteristics allow it to operate in tropical climates. 
Frequency response: 50 to 10000 cycles/s
Output voltage: 1000 cycles/s in open circuit and at a sound pressure of 1 µbar are respectively, depending on impedances of 10000, 500 or 50 ohms, -72 dbv and -82 dbv