Switchcraft Microphone Jack 3 Circuit- SWCS12B- JJ-033.
Contact springs are of special alloys for long life. Insulation is high dielectric strength phenolic. Tinned terminal lugs for easy soldering. Short frame. Mounts by 3/8-32 threaded bushing and nut. Open circuit until plug inserted.
Yes, this is the size needed for the small microphone plug that is part of the dual GA twin plugs most David Clark headsets are outfitted with.