Stereo wireless headphones Transmission frequency: 2,4-2,48 GHz Modulation: digital Max transmission power: 9,9 dBm Operational range: up to 50m Dual, interference free antenna FM Radio with autoscan FM Radio tunning band: 87,5 – 108 MHz Frequency response 22Hz – 20kHz Digital volume control and power switch Up to 8 hrs operation time (depends of distance, environment and personal habits) Power: for headphones built in lithium battery or 2xAAA alkaline batteries, for base 3 x AAA alkaline batteries or 5V power adaptor Headphones weight:260g (without battery) *)NOTE. Batteries and rechargeable batteries are not included!