Features - EASY TO USE: With handy on and off button and volume control that allows the user to make accurate adjustments in no time. - COMFORTABLE: silicone ear buds won't hurt your ears, offering the most comfortable wearing. - WIDE USE. Suitable for hard-of-hearing users, the deaf, the elderly, the hearing-impaired, etc. - PREFERENTIAL GIFT BOX. Different size noise cancelling earplugs for selection and a storage box is included. Specifications - Color: As shown - Material: ABS, silicone - Item Size: 10 x 9 x 4 cm - Type: Mini BTE Hearing aid - Max Sound Output: 130dB plusmn; 5dB - Max Sound Gain: 50dB plusmn; 5dB - Harmonic Wave Distortion: le;5% - Frequency Range: 300~4000 Hz - Input Noise: le;30 dB - Battery: AG13 Button battery (Included) - Working Voltage: dc1.5V - Working Current: le;4mA Note: - Adjust volume to the minimum before wearing, and increase volume gradually to avoid sudden increase in sound. - Choose an earplug of slightly bigger size to avoid whistler. - Increase volume gradually to avoid sudden increase in sound. - If you hear a howling, check the ear (silica gel) is appropriate and whether the size of plug is tight, the appropriate choice of earplugs and plugged, make sure no air leakage. - Keep the ear plug clean. - Remove the battery if you don't use it for long time.