The K-PO NM-532 P4 is wired for Standard 4 Pin Cobra/Uniden Radios. 
These radios need the wire connected on Pin #4 for sound to come out of the radio's speaker. If you unplug the microphone on a radio like this, you will not have sound out of your speaker.
High quality power microphone to enhance audio sound.It features a slide volume control and on air indicator light.This microphone is suitable for most CB and 10 Meter transceivers with a 4 pin connector.
Omnidirectional electret condenser
Sensitivity: -42dB (AT 1 KHZ)
Impedance: 1000 Ω  (AT 1 KHZ)
Frequency: 300HZ – 6 KHZ
6 Foot Cord (1.80 m)
Heavy-duty ABS shell
105 × 70 × 35 mm
9V battery included