The Altec 639. Originally the Western Electric 639, this microphone enjoyed a long life even after the Federal government-mandated breakup of Western Electric in 1947 (Altec was the pro-audio spinoff).

This particular speciman, mounted on a custom lucite base, was originally used by CBS Television in Los Angles. Both a ribbon and dynamic element were incorporated into the design. A switch on the rear of the microphone selected either ribbon, dynamic, or a combination of both as the active pickup elements.

The 639 was nicknamed the "birdcage mic" because of its resemblence to a birdcage.