Audio 2000s AWM6528U518 4 Channel UHF Wireless Microphone with Headband Headsets UHF Band Frequency (comply with new FCC rules) 50 Selectacble frequencies per channel and up to 12 systems can be used simultaneously. Four Independent XLR Balanced Audio Outputs One 1/4" (TS) Unbalanced Mixed Audio Output Four Volume Control Knobs (One for Each Channel) at the Front Panel