The DVM-25T is a compact,single stick version of the Digi Volt voltmeters. It requires one 9V lithium or alkaline battery, which powers the unit and activates the back light. The meter will shut off automatically a few minutes after the display reads zero, but not while voltage measurements are being made. The DVM-25T includes an elbow test point reading feature, which is displayed by a blinking decimal point ( ). The back light is always on when the unit is powered on. The low battery feature will simply shut off or will not turn on the meter when the battery is low. The unit has a 0.4" LCD display that indicates 3-1/2 digits. The DVM-25T measures RMS AC and DC.