Specificaiton Charging Current DC5V 50MA 1A Lithium Battery 60MAH Battery Size 45 40 10MM Weight About 6 5g Maximum Sound Output 129±4DB Sound Gain 38±5DB Harmonic Distortion ≤5 Frequency Range 400Hz 3800Hz Voltage 3 7VPackage Included 1 x Sound Amplifier Earphones