Few microphones of the 60's were more successful in design yet horrible in performance than the common Argonne AR-57 dual crystal element microphone. Variously labeled as a house brand, this RCA 77C inspired inexpensive mic has all the visual detail that 60s Japanese electronics packaging was known for. The exuberant and colorful designs of thousands of Japanese transistor radios shared elements like ribbed chrome rings, a real cloisonne emblem (claws on a, not cloy son a - geesh!) and mother of plastic and chromium plated details galore.
Two rochelle salt crystal elements are connected in parallel to lower the output Z and boost the output level. This mic is hot and produces an amazingly unpleasant ringy tone on any sound source unfortunate to be near.
But it still is and has always been a favorite of mine. These are not scarce and yet they bring over a $100 on ebay, which is about $50 too much in my estimation, given that hundreds of thousands were probably sold.
I saw this mic used as prop on a late nite TV infomercial where some greasy haired dude tries to sell nutriceutical pills.
"Pill Shaped" is how this is often described.