Features
Klein Tools MM400 is an auto-ranging multimeter that measures AC/DC voltage, AC/DC current, and resistance. It can also measure temperature, capacitance, frequency, duty-cycle, and test diodes and continuity. Klein Tools’ 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.


Klein’s MM400 digital multimeter is good to measure up to 600V (AC/DC), 10 amps and 40 Ohms of resistance.

It measures temperature up to 1,000-degrees Fahrenheit, capacitance, frequency and more!

Durable construction, this multimeter is designed to withstand a 1-meter drop.
Measures temperature, capacitance, frequency, duty-cycle, and test diodes and continuity
CAT III 600V safety rating
Built to withstand a 3.3-foot (1 m) drop and withstand daily wear and tear on the job site
Low battery indicator and easily accessible battery compartment
For use in basic and controlled electromagnetic environments such as residential, business and light-industrial locations
Includes test leads, thermocouple with adapter and batteries
Our next generation of test and measurement tools were designed to meet the expanding jobsite needs and expectations of today’s professional tradesman. Tested tough. Trusted safe.

Klein Tools is the result of one of those “happy accidents” that turn out to be revolutionary. Klein Tools famously got their start in 1857 when a linesman came to founder Matthias Klein to repair his broken pliers. Klein replaced the broken half and when the old half of the tool broke too, Klein forged a replacement for that, thus making the first Klein Linesman pliers. Since these humble beginnings, Klein Tools has grown and become one of the largest American made toolmakers and they’re a brand used by tradesmen, linesman and electricians all across America.