Ltb LTB-WR51 24.GHZ Wireless Headphones 2.4GHz digital radio transmission (absolutely noise-free Multiple Speaker Units for Front, Rear, Center, and Subwoofer Channels. 10 mW Transmitting power, 10dBm/Range of 100 Plus Meters. Three Selectable RF channels via Tactile Switch/CMOS Headphone Amplifier Freedom of Sound with Reception Through Walls and Ceilings, Even Outside