Dlyfull Battery Tester, Small Battery Testers Universal Battery Checker for AAA AA C D 9V 1.5V Button Cell Household Batteries...

This is just a darn handy device to have around ... especially for the price! I seem to have plenty of electrical and electronic devices in my life ... that all need batteries. I hate that I have to maintain a small bag of various-sized batteries all of the time, but ... alas ... I just keep the Dlyfull battery tester in my bag with the batteries. I love being able to quickly check a battery, and see if it's been in my bag "too long." But the most helpful part of using this battery tester is troubleshooting my electronic devices when they don't work. Now I can quickly and easily check and at least know whether "the problem" is that the battery or batteries need to be replaced (or recharged!) ... or I have other problems with my devices. This has been a time-saver for me. And, sheesh ... this battery tester is simple, no muss, no fuss. The tester itself doesn't require batteries ... or usb plugs ... or power cords ... or power converters ... to work. Just insert a battery into the tester ... and check it, easy peasy. (Make sure you have the "positive" end of the battery making contact with the "positive" end of the tester!)

Cool and simple way to keep a check on small batteries. It feels a little cheap but it does what I need it to do. No more looking for my multimeter any time I need to check a battery. Just keep this one in the battery drawer.

Device is just what I needed to test a bunch of batteries I have had for while

This is a very simple tester that works with a variety of batteries. The nice thing about it is that it does not require any batteries itself to work.

Lost my other one. This one is good