CLASSICAL DESIGN and NEW CRAFT IMPROVEMENT So this is the wireless infrared stereo headset for car. It's specially designed for in-car backseat entertainment. The headband and ear cups are still adjustable so kids can also customize the fit for all-day listening comfort. Need a reliable Infrared wireless headphones ? Kuuleyn gives you the best choice Specification Channel A 2.8 MHz for the right channel; 2.3 MHz for the left channel Channel B 3.8 MHz for the right channel; 3.2 MHz for the left channel Speaker 30mm for Mylar Cone Impedance 32Ω ± 15% Effective Range (maximum) About 10 Meters Power Source 1 X AAA Battery (not Included) Signal Noise Ratio ≥70dB Channel Separation ≥40dB Frequency Response 30-20,000Hz Audio Model Stereo Automatically Automatically turn on when the wear and shut down when take it out of function