Minn Kota Digital Battery Meter. Use to monitor the voltage level and "state of charge" of any 12-volt battery. Features an LED display that indicates full, 2/3, 1/3 or 0 "state of charge" as well as the voltage of the battery. To use, simply touch the positive lead to the positive terminal on the battery and the negative lead of the probe to the negative terminal. Easy to store anywhere. 1 year warranty.