The RMW921 Wireless Microphone is a professional UHF, PLL controlled, true diversity system providing reliable and high quality signal transmission. The system is equipped with automatic channel scan and IR sync. 99 channel frequencies are available for simultaneous use of 6 devices. The system is available in two different configurations with Handheld or belt-pack transmitter. TRUE DIVERSITY 518-550 Mhz frequency range PLL transmission 50 meter/ 100 feetrange 50 Hz -15 KHz frequency response Condenser headset with cardioid capsule 99 selectable channels Up to 6 frequency usable in the same location ABS carrying and storage case Auto scan channels BNC Antennas.