Features: Professional 4 channel UHF 610-680MHz wireless headset microphone system. High sensitivity, super clear sound, great anti-interference capability. Effective working range up to 80 meters in open-area. With standard XLR balanced and 1/4 mixed output interface. Independent volume adjusting knobs for 4 channels, AF/RF indicator light. One bodypack run on 2 * AA batteries(not included), and supplied with a power adapter for the receiver, 1/4 audio cable. Ideal for classroom, meeting, mall exhibitions, coaches, giving a speech, presentation and public address, outdoor activities etc.