The KOVOT Battery Organizer and Tester hangs easily from your wall or inside of your cabinets. Keep all your batteries organized and in reach for when you need them! The Battery Organizer and Tester holds up to 72 batteries in all the popular sizes: AAA, AA, C, D, 9 Volt and even Button Cells Battery power is indicted by the following lighting combinations: Good: All three lights red, yellow, green are lit Weak: Only the red and yellow are lit. Only red light on: The current in the battery is very low and can barely function. No Light: The battery power is completely exhausted and the battery is completely useless! The tester offers 3 ports to test various types of batteries: Port A: 3v Button Cells Port B: AA, AAA, C and D Batteries Port C: 9V Rectangular Battery