Ultra light design for comfortable wearing; Suitable for car audio system. Up to 12 meters operating distance. Automatic shut-off after 10 minutes of no signal detected. Mini jack for audio input like MP3, . Built-in 30 mm Mylar speaker to deliver audiophile grade sound quality. Package Contents: 2 x Double Infrared Stereo Wireless Headphone Color: Black Material: Plastic System infrared light: 850nm Carrier frequency: A channel: left channel: 2.3Mhz, Right channel: 2.8Mhz B channel: left channel: 3.2Mhz, Right channel: 3.8Mhz Signal to Noise: 60db Channel Separation: 45db Distortion: Less than 1% Frequency Response: 30-20000Hz Power Supply: 2 x AAA Batteries (Not Included) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.