Klein Tools MM300 Multimeter is a manual ranging multimeter that measures AC/DC voltage, DC current, and resistance. It can also test batteries, diodes, and continuity. Klein ToolsÛª Test and Measurement product line was exclusively designed from the ground up by electricians for electricians. Years of field research, combined with extensive input from electricians across America, inspired the development of meters and electrical testers loaded with innovative, time-saving features.