AKG Handheld Dual Wireless Microphones, Channels A/C

The WMS40 Mini Dual Vocal Set is a true plug’n’play wireless solution. Each of the two included HT40 Mini handheld transmitter features a dynamic cardioid capsule for maximum gain before feedback. Their extremely long battery life of 30 hours off a single AA battery saves money in day-to-day use. The receiver offers two balanced outputs via 1/4″ jack connectors.

This is one receiver and two mics, and it plugs into one channel of your mixer, or into the back of a powered speaker. 

Because these two mics operate on fixed frequencies, they work best when there aren’t other wireless mics on or near the same frequencies in the same location.  This setup uses channels A and C, which are frequencies:

A 537.500 MHz
C 539.300 MHz