S-303 this model can be help you solve these problem  hear well in your future life .
Features:

– 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 andplugged, make sure no air leakage.

– Please regularly clean the ear plugs or ear molds in order to ensure the normaluse of hearing aids.

– Use for long periods of time, please remove the batteries to prevent batteryroterosion hearing aid components

Package content:

This model use zinc air battery A13 ,can last more than 600hours one pcs.

The hearing aid will be automatically change the sound until you hear comfortable according to different environment ,.program switch is automatically change ,with noise reduction

This product is a delicate ear hearing aids, especially use for your entertainment,leisure, listening to opera, watching television and movies, meeting communication or students in the class, to make the sound effect clear and lound,good choice for people who need.

Low Frequency Adjustment