When wiring an electret microphone is using the wire shielding as

The Cable Connection: Balanced and Unbalanced

Locus Sonus - Electret mics

Getting one wire to do more, Part 2 – Phantom power for the microphone

Why do microphones have 3 wires? - Quora

UHF Transmitter 5-pin Input Jack Wiring

Electret microphone with wires.

Small Electret Microphone with Long Wires with Shield + Dustscreen 10mm x 11mm

Electret Condenser Microphone: Back electret type, small in size, in general use. Come with a 2 wire cable for easy connectivity to your device

uxcell 10Pcs 6mm x 3.5mm 2 Wire Cable MIC Electret Condenser Stereo Microphone High Sensitivity 3.5mm Electret Microphone

Vidpro XM-L Wired Lavalier microphone - 20' Audio Cable - Transducer type: Electret Condenser FOR Canon VIXIA HF R500 Camcorder : Electronics