Voltcraft button cell tester voltcraft 250455 test lithium coin cells and alkaline button cells quickly and easily with the voltcraft button cell tester simply insert the cell into the tester which will identify whether the cell is lithium or alkaline and indicate this via an led 5 other leds show the remaining capacity of the cell at 1 led the cell needs replacing 2 3 leds the cell is weak 4 5 leds the cell is suitable to use as the tester has its own internal battery and does not dr