The ultra-high frequency (UHF) microphone system minimizes radio frequency interference and noises generated by other electronic equipment and digital devices. Easy to set up and operate with preset dual-channel UHF frequencies and independent volume controls (540.9 MHz and 581.4 MHz). frequencies are Compliant with the Federal communication commission rules Quartz crystal oscillation stabilizes frequency transmitting and receiving with two detachable Antennas, making sure the sound quality is reliable and consistent Audio compressing-expanding technology can minimize noise and boost dynamic range. The Cardioid microphone pickup pattern produces superb feedback and off-axis rejection Up to 200 feet operation range with stellar sound quality. Ideal for conferences, Broadcasting, weddings, Karaoke, social events and medium-sized venues such as meeting rooms, schools, churches.