Gardner Bender GBT-500A Battery Tester
Gardner Bender designed the functionality of this tester very well, starting with the meter interface. The red to green gauge is simple and easy to understand, offering readings for general purpose, nickel cadmium and button lithium cells with one needle. Red and black tester leads are attached with wires and easy to manipulate, instead of installing batteries into contacts within the unit itself. The GBT-500A is also highly accurate to testing the amount of actual current left inside of the cell as opposed to reading only the voltage. This will cut down on false positives as dead batteries will read proper voltage even if they're out of juice. So you can be sure when it's time to trash those dead cells instead of sticking them back in your camera or remote control.