Mercury Universal Battery Tester is a compact and easy to use device designed to check the charge level of common household batteries. Compatible with AA, AAA, C, D, 9V PP3 and coin button cells, it provides a clear analogue display showing battery condition as Good, Low or Replace. The tester uses power from the battery being checked, removing the need for additional batteries. Ideal for home, office and workshop use, it helps identify battery status quickly and prevents unnecessary replacement of batteries that still have usable power. Packaging may vary.