The Ansmann Energy 4 Speed Set is a microprocessor controlled fast charger. The charger can be used to charge 1 to 4 AA or AAA rechargeable batteries. The charging current is optional from 2100 or 850mA for AA size and 850 or 350mA for AAA size. Features of this charger include Special cooling technology deltaV charging technology temperature control cell temperature Tracking Zero Delta V detection and trickle charge function.The Ansmann Energy 4 Speed charger is powered by an external switch mode power supply, it is possible to use this charger worldwide and also via the 12V car socket adaptor. Charges 1 4 AA or AAA Adjustable charging current by a switch Fast charge Standard charge 2100mA850mA for AA cells and 850mA350mA for AAA cells Multiple over charging protection by deltaV detection, temperature control and safety timer Trickle charging faulty cell and Alkaline detection Reverse polarity protection Cooling of the batteries by a fan Battery status is displayed by LED per charging slot External power supply with wide range input 100 240V AC and 12V car adapter