Frequency Sets: 9A, 9B, 9C, 9D Complies with New FCC Frequency Rules 4 individual XLR Mic Outputs and 1 1/4' Mixed Output 4 Handheld mics included Individual Volume controls for precise vocal balancing 4 independent Field-replaceable Modules Interference-resistant UHF Band operation Rugged 1RU metal receiver chassis Low power consumption design for longer battery life