Recharges up to four AAA, AA, C, or D-size Nickel-Metal Hydride (Ni-MH) or Nickel-Cadmium (Ni-Cd) batteries or two 9V cells singly or in a group. Manual selector for battery type, and automatic charging current selection for battery size. LED indicates correct charging. Built-in timer allows fast charging in the specified period with automatic switch to trickle charge. Charging time with timer is 5-8 hours, depending on battery type, 10-15 hours with manual control.