Switchcraft Stereo Headphone Jack- 3 Circuit Conductor with Nut and Washer, Double Open Circuit- SWC-12B.
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.