C2G/Cables to Go Audio Unlimited 900MHz Wireless Rechargable Stereo Headphones (SPK-9100) Transmitter connects via 3.5mm audio cable to PCs, MP3 players, iPods, stereos and home theatre systems. Headphones can be up to 165 feet away from the audio source, without line of sight limitations. Automatic battery recharging ability built into the transmitter that doubles as a headphone stand Earphones are battery powered (using 2 AAA rechargeable 1.2V batteries - included). Compact and portable with a lightweight, over the ear, stylized design 40mm Woofers 10W RMS Output 2.4V DC Transformer Transmitter connects via 3.5mm audio cable to PCs, MP3 players, iPods, stereos and home theatre systems. Headphones can be up to 165' away from the audio source, without line of sight limitations. Automatic battery recharging ability built into the transmitter that doubles as a headphone stand Headphones are battery powered (using 2 AAA rechargeable 1.2V batteries - included). Compact & portable with a lightweight, over the ear, stylized design 40mm Woofers 10W RMS Output 2.4V DC Transformer