Convenient: just check the current battery status | Very suitable for determining whether the battery is used in the drawer, etc. can quickly measure the battery voltage and display the test result. Flexible use: suitable for AAA, AA, C, D, 9V and other battery types | There are two different contact points on the device, for measurement 1.5 V + 9 V batteries can be used The operation is simple: insert the battery in the direction of the polarity - read - it's ready. | slider adaptable to different battery sizes | tricolor simulation gives clear results | No additional power required Easy to read: The portable design is easy to read. No batteries required: The battery tester is activated by the battery to be tested and can work without batteries. Test the battery life anytime and anywhere.