A handy, compact battery tester for a wide range of batteries: AAA, AA, D, C, 6F22/PP3 9V, A23, LR1 and button cells. Easy-to-read charge-level display. No additional battery power required. A handy, compact battery tester for a wide range of batteries: AAA, AA, D, C, 6F22/PP3 9V, A23, LR1 and button cells. Easy-to-read charge-level display. No additional battery power required.