Tweeze Your Buttons
TWEEZER COIN/BUTTON CELL TESTERS
These super handy little tweezer-style battery testers are made for checking button-cell and 3V lithium coin-cell batteries, but they've got a wide enough spread for everything from "AAA"s to D-cells (but not 9-volts!). Red and black arms designate the +/- sides, and an LED at the base lights up if the battery is good. Expect a dim glow for 1.5V and it's best seen in a dark room, and a bright glow for 3.0V.