Tried of rummaging through your stack of batteries without knowing which ones still have juice and which ones are dead? With the IOGEAR Battery Tester (GBT001W6) you can easily determine whether the battery you are using is charged or not. Simply connect your AA, AAA, C, D, N, 9 volt or even a 1.5 volt battery to the negative and positive poles of the battery tester and the easy to read gauge will automatically let you know if that battery has juice or is empty. Keep the battery tester on your keychain or conveniently store this handy compact device in just about everywhere. Now you can be sure that your kids toys, your gadgets, gizmos, and other equipment stay powered no matter what. The easy to read display tells you instantly whether you have a dud, or if you can eke out another few minutes of battery life.