Although I have a good digital multimeter, I often prefer to check batteries with this small device - it's quick and easy. This tester actually measures a voltage, applying a medium load to the battery (150...300 mA), which gives more realistic test. The scale shows no volts, but instead has "Good/Bad" sectors. You should get some understanding what is "good" and what is "bad". For example, the same battery may be good for TV remote, acceptable for pocket torch, and absolutely dead for digital camera. A single thing which I don't like is the shape of measuring lever. I still cannot learn how to operate the device with a single hand - it tends to jump out of my hand. Possibly, it's a cost for compact size.