The other day, I finally had it with the crazy battery situation in my house. We had loose batteries scattered throughout several drawers in the kitchen - and no one ever knew which worked and which were dead. If you found yourself in need of a fresh and charged battery - it took hours to get your gizmo working because you inevitably had one bad battery amongst the four you needed! So one day strolling though the isles at McLean Hardware I came upon a battery tester for about $11. And all the battery pain we had experienced flashed though my mind and I said - "Never again! We're buying it!" And let me tell you it was money well spent. I went home and the kids thought it was a fabulously fun project to test all the batteries and throw out the dead ones and store the good ones in a orange shoe box. Now we know that every battery in the box works!! EFFICIENCY!