VocoPro  IR-9000 Infrared Dual Rechargeable Wireless Microphone System The IR-9000 uses infrared technology instead of the UHF or VHF bands, eliminating signal interference like never before The included charger charges both microphones so you never have to worry about changing dead batteries Have multiple IR-9000s in different rooms and no interference 2 Microphone channels, each with individual volume controls Includes 1 external IR sensor for better reception in larger rooms