The digital multi-cell lithium battery voltage LED display is used for up to 4-cell L-Po batteries. The display is with reverse polarity protection and low current consumption. The LED display is an amazing gadget which displays the voltage of each Cell Bridge and then total. It shows you which battery cells need to be balanced and also shows you when you need to dispose of your battery because of a dead cell. -Used for up to 4-Cell Li-Po Battery -Auto shift the voltage data one unit by one unit -Only 9 gram weight can be used on plane -Reverse polarity protection -Low current consumption