1 Pin 3.5mm Receiver/Listen Only Surveillance Acoustic Tube Earpiece Compatible with Two-Way Radios Transceivers
https://www.vogueparade.com/shopping/EN/200380144/1/1005003329796597/1-pin-35mm-receiverlisten-only-surveillance-acoustic-tube-earpiece-compatible-with-two-way-radios-transceivers//