Our A/C Charger uses 3VDC AC to DC adapter to recharge your NiMh hearing aid cells. Our NiMh hearing aid cells range from 18 mA for the #13s through 40 mA for the 675s. The charging power of the adapter insures a quick charge for our hearing aid batteries. Our batteries will give 20-40 hours of usage depending upon the power requirements of the hearing aid(s) before they need to be recharged. The AC DC adapter provides a simple method for NiMh battery recharge. The battery tester is a handy way of testing your hearing aid cells to make sure that they are fully charged.