1. No power required: Universal rechargeable battery tester is activated by the battery to be tested, so no batteries are required for operation. Thanks to the adjustable slider, the battery tester is compatible with most batteries and button batteries.^ 2. Accurate test results: The digital battery tester is faster and more accurate than the average battery tester. You can use it to find out battery usage without having to wait.^ 3. Easy to read: The digital display immediately shows the battery capacity. There is a summary table behind the product, you can see the performance of all types of batteries at a glance compared to the numbers on the back.^ 4. Ease of use: Check that the battery is touching the two contacts of the tester and read the numbers on the LCD display. You can decide whether to replace the battery based on the current performance status of the battery.^ 5. Easy to Carry: The LCD battery tester is a simple and effective battery tester, suitable for AA, AAA, C, D, 1.5V, 9V and button cells, which is small and light, so you can use it in daily life and travel .