Another name for 3LR12 batteries is lantern batteries. Just like the name suggests, these flat batteries are most commonly used in lighting devices like flashlights, headlamps, torch lights, and construction lights. This is because the power requirement of these lights is suitable for the power output of these batteries. However, that doesn’t mean these batteries are not used in any other type of application. Another common application of these batteries is in uninterrupted power systems, in which many numbers of these batteries will be coupled together to give a much higher voltage output.