Checks battery condition instantly and accurately. No outside power source needed, simply touch either the positive or negative side of battery to the corresponding contact point on the tester face and then touch the correct test lead to opposite side of battery. The scale indicates a weak battery when the needle drops with an easy-to-read selector switch and color coded "Good/Replace" indicator. Tests battery automatically. Tests: 1.25V Ni-Cad rechargeable, 1.5V button cells, 3V lithium, 6V, 9V, 12V & 15V photo cells, 22.5V lantern cells, AA, AAA, C, D, N.