This is only for the charger. It's compatible for iBstone K17 / K18 hearing aids.
There are power indicator light and two charging indicator lights. When the charger is started to charge, all lights will flash blue for a second. Then the charging indicator light will start to work. It will flash red light when charging, and stay solid blue when fully charged.
It's will takes 3-6 hourse for a full charge, and then can be used for around 20-24 hours.