[Test Different Battery Types] A summary table is written on the back of the product to understand the display contents. Suitable for all types of standard batteries and rechargeable batteries: AA, AAA, C, D, 1.5V, 9V and button batteries. The adjustable slider makes the battery tester compatible with most batteries.[No Battery Required] This universal battery tester is excellent in emergency situations. It is powered by the battery it is testing, so it can work without a battery.[Easy to Read] The digital display immediately shows the battery level. There is a summary table on the back of the product, which allows you to check the different types of battery power at a glance with the numbers displayed on the back.[Must-Have Tools] The battery tester is a tool used in our daily lives to check if the battery is intact, low in power or needs to be replaced. A must-have for anyone who regularly uses standard or rechargeable batteries. [Small and Convenient] Simple and effective battery tester, small size, lightweight, easy to carry, test battery life anytime, anywhere. Trust the quality of our products. Our battery testers have been well tested before leaving the factory. Therefore, when you put the battery out of use, please try testing again with another battery.