The special feature about this charger set is that the batteries are READY TO USE , that means Once it is charged they can be used anytime anywhere up to One Year..This charger is designed to charge Nickel Metal Hydryde NiMH and Nickel Cadium NiCD AA and AAA type Rechragable batteries . It quicklyy Recharges from to 4 AA or AAA type Ni-MH or Ni-CD Batteris. It has micro processor technology for better usage of power consumption and charge management , The LCD display Panel indicate the status of carging , The USB slot can be used to charge mobile phones or mp3 players etc. The Trickle charge technology would be used just after the batteries are charged.