RF Listening Center Additional Headphone

W901-MULTI Style: Blue (72.500 Mhz) The RF Listening Center Headphones operate on four separate frequencies allowing multiple systems to be used simultaneously in the same room and with their rugged lightweight construction, they are perfect for use in the class room. Features: -RF Listening Center additional headphone -Forty hours of operating time between charges -One hundred feet transmission range -Any number of headphones can be used with each system -Plug and play simplicity -No interference from other electronic equipment, operates on dedicated channels, no external antenna -Charges in four hours, operates for forty hours -New Classroom friendly, mercury free, nickel metal hydride (N1-MH) battery -LED charging indicator lights - red for charging, green for fully charged -One year warranty .