PUSH TO TALK
Shure 91A27, Carbon, USA, 1940s
Philips (or Steane's) 1108?, Dynamic?, Australia, c.1955
3M C00HHA0321 798066 (OEM Turner 253), Dynamic, USA, 1960s?
Philips 1100 or 1101 (Dynamax), Dynamic, Australia, 1958
Philips 1100 or 1101 (Dynamax), Dynamic, Australia, 1958
Philips 1108?, Crystal, Australia, 1955
Automatic Electric Co. CAU 51010, Dynamic, USA, c.1940
Zephyr 80MA, Dynamic, Australia, 1958
Astatic 200s, Crystal, USA, 1950
PYE PTC 4001 E.M. (Tulip), Dynamic, UK, 1958
RCA CX 55, Crystal, USA, 1950s
