Item Type: Sound AmplifierMaterial: ABSMaximum Sound Output: 120+3dBSound Gain: >= 30dB5dBTotal Harmonic Distortion: < 10%Frequency Range: 450-4500MHzInput Noise: <32dBCurrent: 1.2mABuilt in Lithium Battery Capacity: 25mAh (included)Package List1 x Sound Amplifier1 x Charging Base1 x Charging Cable1 x Manual5 x Earplug1 x Brush1[KNOB TYPE SOUND CONTROL] This sound amplifier device uses a knob type sound control to adjust the volume. 2[WITH 5 EARPLUGS] The aid headphones come with 5 silicone earplugs that are soft and elastic, effectively relieving ear discomfort. 3[COMFORTABLE TO WEAR] The portable sound amplifier fits the contour of your ear for extra comfort all day long. 4[RECHARGEABLE FUNCTION] This hearing amplifier has a built in rechargeable 25mAh lithium battery (included), convenient to use for you. 5[PORTABLE DESIGN] The rechargeable hearing amplifier is compact for easy portability. Easy to operate for seniors.