3 Modes for Continuity and Voltage Testing:Mode 1: Continuity tester for unpowered circuits. 0-10 ohms, usesÿ35121 Lampÿwith two AAA batteries (not supplied). Mode 2: Voltage tester 60-600 volts AC or DC when 35121 Lamp is used without batteries. Mode 3: Voltage tester 0-60 volts AC or DC when various lamps are used without batteries. Range: 0-600 volts or 1-10 ohms. Probe: 3 volts at 270 ma maximum. Batteries not included. Requires 2 AAA batteries for testing unpowered circuits. Low voltage lamp tests unpowered circuitry