It is not necessary to install the ear hook for use at home, and it is better to install the ear hook when go out or some intense exercise. The ear hook can better secure firmly close ear hearing aid, in order to avoid the hearing aid drop down in the process of using. Help people with hearing impairment to hear sound and voice Bluetooth style, powerful hearing aid Removable ear hook design With batteries and different size ear plugs Specification: Brand: AXON Model: V-183 Max Sound Output: 1294dB Max Sound Gain: 55dB 5dB Frequency Range: 250~3800Hz Working Voltage: DC1.5V Battery: AG13 or A675 Zinc Air Battery Package included: 1 x AXON V-183 Bluetooth Type Hearing Aid Volume Adjustable Voice Amplifier 3 x Earplugs (different sizes) 2 x Batteries 2 x Ear Hooks 1 x User Manual