This faithfull battery tester is simple and easy to use on most types of standard domestic and rechargeable batteries it helps to ensure the batteries are fully charged and ready for use a simple analogue needle display indicates the power level of the batteries good low or replacement required an adjustable arm allows the tester to accommodate the testing of d c aa aaa 9v 6f22 batteries and 15v button cells and folds down for easy storage features analogue needle indicator tests d c aa aaa 9v 6