Add on Flesh Tone Single Over Ear Mic Kit User selectable wireless Panel Mount Receiver (factory installed) Frequencies 584 to 608 MHz. Wireless 16 Channel UHF Flesh Tone Single Over-Ear/Headset Electret Mic Kit - unidirectional, user selectable wireles Panel Mount Receiver and bodypack transmitter (S1690T) requires two "AA" batteries (included). Frequencies 584 to 608 MHz. Used with SW725, SW800.