Switching power and car adaptor design Super rapid charger (fastest time: 55 minutes) Exclusively for use with AA/AAA rechargeable batteries of Ni-Mh (Nickel-Metal Hydride) and Ni-Cd (Nickel Cadmium) type. Charge up to 4 AA batteries or up to 2 AAA batteries at once Multi-level protection circuit providing over-charge, over-voltage and short circuit protection. Reverse polarity protection. Four individual charging slots for mixed AA and AAA Ni/MH or Ni/Cd cells. Delta V and zero slope voltage detection Non-rechargeable, fully charged battery, defective and poor quality battery detection.