I have a small, handy and lightweight device only recently and am really excited! It is durchzutesten able almost all batteries Photo batteries and button cells (also rechargeable). Frequently used devices that are operated with such power four or five pieces of batteries and button cells. If a device then stopped working all the batteries have been disposed of with me often. Since I have the device, I realize that often only one battery is empty. The device has already paid for itself a few days after purchase: For me and the environment! For operation of the device is not much to say, it is very easy to use, moreover, is not an instruction manual at. I would like to point out that the battery tester is a AAA cell requires 1.5V to operate the little tester (included).