Light Weight Design For Comfortable Wearing-Small Ear Size Fits Children Well-Auto Mute On Headphone-Auto Power Off Function On Headphone * Personal Volume Control-Dual Channel-A Channel: Right Channel: 2.8mhz; Left Channel: 2.3mhz-B Channel: Right Channel: 3.8mhz; Left Channel: 3.2mhz-Speaker: 30mm Mylar- * Cone Impedance: About 32ohmEffective Range(Maximum): About 10 MetersS/N Ratio: 70db(Minimum)Channel Separation: 40db(Minimum)Frequency Response: 30-20000Hz * Power Supply: 2 * AAA Battery * Effective Range(Maximum): About 10 MetersS/N Ratio: 70db(Minimum)