1、[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. Item Type: Sound Amplifier Material: ABS Maximum Sound Output: 120+3dB Sound Gain: >= 30dB±5dB Total Harmonic Distortion: < 10% Frequency Range: 450-4500MHz Input Noise: <32dB Current: 1.2mA Built in Lithium Battery Capacity: 25mAh (included) 1 x Sound Amplifier 1 x Charging Base 1 x Charging Cable 1 x Manual 5 x Earplug 1 x Brush