With this device, you can test both alkaline and lithium cells. This allows you to accurately determine when button cells can still be used or when they need to be disposed of. User-friendly and compact, the handy device fits into any pocket, ensuring that you always have the tester on hand to check your cells. Once you place and press a button cell, the tester automatically detects the voltage and displays it via the corresponding LED status indicator. The capacity is shown through five LEDs. The current capacity of the cell is tested under load and indicated by the LEDs in red, orange, or green. This way, you always know how full or empty your cells are. A CR 1620 battery is included for operating the testing device.