Klein mm400 Review

Best Klein mm400 Review 2022

In this Klein mm400 review, we will be trying to explore almost everything about this product. Klein mm400 is one of the amazing tech-oriented innovations in the field of an auto-ranging multimeter. Photo Credit By: Pro Tool Reviews

A noticeable advantage of such types of digital multimeters is that they can detect and measure the electrical values automatically without any flaws or glitches.

From becoming a laymen’s favorite to a professional electrician’s quintessential tool, auto-ranging multimeter delivers sturdy and reliable performance.

A Comparison Table of Klein mm400

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Coming power-packed with the finest features to meet the industrial standards of perfection, a multimeter is an exceptionally brilliant tool for all tech-savvies.

If you are exploring the best multimeters in the segment, then do not miss out on the Klein mm400. Being an auto-ranging multimeter, it delivers remarkably efficient performance in measuring the electrical parameters with the highest accuracy.

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Considering the legacy of providing the best-in-class technical gears, Klein mm400 is the one of best affordable picks that come with quality assurance.

Best Klein mm400 Review 2021

Being a highly reliable and sturdy gear, this multimeter has managed to reap fruitful outcomes. Another promising aspect of this multimeter is that it comes with the safety integrations.

To provide you with all the necessary details, features, integrations, and specifications, the following is a comprehensive review of the product.

To throw some light on the features and functionalities, the following is an in-depth best multimeter test leads that would provide you a better understanding of the product and its utility.

Klein Tools-MM400 Multimeter, Auto Ranging Digital Electrical Tester

Klein mm400 Review
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Coming from one of the leading brands in the segment, the Klein MM400 auto-ranging multimeter has been designed specifically for measuring the resistance along with AC/DC voltage and current.

Furthermore, it is also efficient in measuring frequency, temperature, duty-cycle, continuity, test diodes, and capacitance as well.

Designed by the expert in-house electricians, this tool is exceptionally advantageous for residential as well as commercial use.

Also, the efficiency and accuracy of this multimeter are quite impressive as it can measure AC/DC voltage and current of up to 600V and 10A, respectively.

Talking about the resistance, this technical tool can measure a range of up to 40MΩ that is quite satisfactory in the segment.

On an additional note, you will also get 2 AAA batteries, an adaptor, and an instruction manual, along with a thermocouple for measuring the temperature.

Another highlighting aspect of this multimeter is that it comes with the integrations crafted, especially for safety assurance. For this, it possesses two onboard fuses. 

Klein Tools Mm400 Manual

One fuse is for the high current circuit of 10 A, whereas the other one is 500mA that is positioned on the main terminal. Both the fuses are made with ceramic of HRC type that delivers input protection of top-notch quality.

Apart from this, it comes with a safety rating of CAT III @ 600V for durably robust and power-packed performance. Besides this, the circuit for lower current is integrated with other test ranges as well.

Built exclusively to withstand the regular wear and tear on the commercial or job site, this multimeter can withstand a drop of 1m or 3.3 foot. Beyond this, it runs to AAA batteries that are considered to be more budget-friendly as compared to the highly lavish 9V batteries.

To check the battery percentage, an indicator for detecting a low battery is also given. An easily accessible battery compartment further complements it. 

Another impressive aspect of this tool is that it is versatile in terms of compatibility. One can quickly and conveniently utilize this multimeter in controlled as well as basic electromagnetic environments, including light-industrial, business, and residential locations.

Loaded with user-friendly functionality, the temperature is shown through the standard input method in either Celsius or Fahrenheit.

Also, the quick-witted inclusion of a thermocouple with this multimeter simply assists in the plug-ins through the common connection or the main terminal for displaying temperature readings.

Spilling beans on the worthiness of this multimeter, it offers satisfactorily versatile test ranges under a budget-friendly price tag.

Emphasizing this device’s build-up, it would not be unfair to conclude that this gear has incorporated the best-in-class materials to deliver long-lasting performance.

Klein Tools mm400 Review

Featuring a sturdy and stylish build-up, this compact tool can be carried anywhere with greater ease. Other than this, the rugged holster made out of rubber helps to protect this device from inevitable damages.

With the rubber feet and a flip-out stand, this multimeter offers a comfortable and non-slip grip. On the positive side, the dial of this device is reliable and can be easily turned with a one-handedly operation.

Also, the buttons are soft, rubbery, and enormous for a hassle-free and convenient application. Due to the embedding of a separate compartment, the batteries can be easily changed and replaced for an uninterrupted performance.

In addition to these striking aesthetic features, this multimeter consists of lead wires that are pretty much flexible as well. There is a lot more about the product in this best multimeter test leads.

An aspect that manages to impress is the satisfactory display of this device. Despite lacking an ultra-high-resolution, the backlit display of this multimeter is precisely clear and easily readable too.

With a standard resolution of 4000 counts, the display discerns the signals that were there at the generic level.

Having a frequency sampling of three times per second, this device is efficient to deliver a remarkable performance at an affordable price in the segment.

Above all, an exciting feature that garners the critics’ limelight is the option of an auto-shutoff. For longevity of performance, this auto-shutoff feature is very handy as it shuts down the device after 15 minutes of inactivity.

Such type of integrated functionality is very useful for maintaining the efficiency of the device too. Let us also have a glance on product features, specifications along with its pros and cons in this klein mm300 review.

Product Features of Klein mm400 Review

  1. Efficiently measures AC/DC voltage and current of 600AV and 10A respectively
  2. Capable of determining the resistance of up to 40 MΩ
  3. Withstands a drop of 3.3 foot or 1m along with inevitable damages
  4. Comes with a safety rating of CAT III @ 600V
  5. The option of auto-shutoff after 15 minutes of inactivity 
  6. Consists of thermocouple, adapter, leads, and batteries as well

Product Specifications

  1. Brand: Klein Tools
  2. Model: MM400
  3. Weight: 3.52 ounces
  4. Dimensions: 1.78 x 3.07 x 6 inches


  • A compact yet robust build-up
  • Flawless display complemented with a backlight
  • Consists of micro-amps along with auto-ranging system
  • Leads are flexible for convenient usage


  • Lacks an ultra-high-resolution display

Buying Considerations of Best Multimeter for Home use Review

To get the best multimeter that perfectly fits your requirements, you should assess the pivotal factors. For this, the following buying considerations would guide you to make a worthy choice.


A foremost thing to consider is the type of multimeter that you want to buy. For this, you need to consider your requirements and compare the best suitable ones in the segment.

There exists a vast assortment of multimeters ranging from basic to professionals, from industry to automotive as well.


When it comes to selecting a multimeter, a good display is something that you cannot miss on. If you need a multimeter for the standard household purposes only, then a clear, backlit display would do the needful for you.

However, for advanced industry purposes, you would need a super-high resolution display.


An option of auto-shutoff gives you an added benefit to keep the efficacy of the device in-tact by shutting it down after several minutes of inactivity.

Most of the time, we often forget to shut down the multimeter after use. This can adversely affect the power and performance of the device.


Whenever it comes to purchasing technical gears, price plays an important role in determining the worthiness of the product. You should compare and assess the multimeter features regarding its price tag to make a fruitful choice.

Batteries Power of Klein mm400 Review

Make sure to get a multimeter that runs on the affordable AAA batteries for durable and quality performance. If your multimeter uses posh 9V batteries, then you have to spend a hefty sum of money to keep your device charged for power-packed output.

Safety Rating

For optimum security and protection, the device must hold a satisfactorily reasonable safety rating. In the absence of such a rating, your device would be less secure to the inevitable glitches. Most multimeters are classified on the CAT rating ranging from I-IV.


One of the biggest concerns while choosing a multimeter is the assessment of its accuracy. Those multimeters that have high accuracy power rating would work exceptionally well in measuring the concerned parameters more precisely.

Current and Auto-Ranging

Those multimeters that do not offer an impressive current range often fail to deliver seamless performance. That is why it is necessary to select the gear that comes with a high range of current for unmatchable and reliable performance.

Also, an efficient auto-ranging system helps to test and measure the parameters with an automated range without any hassles.

Frequently Asked Questions (FAQs) of Klein mm300 Review

What are auto-ranging multimeters?

Auto-ranging multimeters are those devices that can change their internal range automatically to measure the resistance, current, and voltage with high accuracy as well.

Due to the auto-range feature, a multimeter is capable of delivering impeccably accurate performance even though the measuring parameters keep fluctuating.

What are the diverse components that are present in an auto-ranging multimeter?

An auto-ranging multimeter consists of three main components, namely a display unit, selection knob, and the ports. These functionalities assist the multimeter in delivering a seamless and power-loaded performance. Each component plays a pivotal role in the smooth functioning of the device.

How to use an auto-ranging multimeter?

Using an auto-ranging multimeter is not rocket science. By following the below-mentioned steps, you can easily make the most out of this device.

  • To measure the voltage, firstly, get the probes in their right place
  • Next step is to plug your black probe into the COM and the red probe into the mAVΩ
  • Connect the red probe to the positive (+) terminal and the black one to the negative one (-)
  • To set the auto-ranging multimeter for voltage measurement, you can use the selection knob
  • Now, you will be able to see the accurate reading on the display screen of the multimeter

What is the purpose of an auto-ranging multimeter?

You can use an auto-ranging multimeter for measuring voltage, resistance, capacitance, wattage, imbalances, and other electrical components.

Due to the in-built auto-ranging functionality, the multimeter can automatically detect these parameters to measure them accurately.

Also, there is no need for a supplementary ranging tool as the device will adjust the manual settings automatically to find the electrical range.

What role does a rectifier play in the multimeter?

When you use a multimeter to measure the AC voltages, there is a rectifier in use. Besides this, the rectifier is also good for accomplishing the input conversions of the voltage AC into DC. Such conversion is mainly done to measure the AC voltage faultlessly.

Which industries can use auto-ranging multimeters?

Auto-ranging multimeters are highly versatile in terms of application and compatibility. Due to this, sectors such as households, offices, industries, and automotive are the primary users of the auto-ranging multimeter.

Also, the integrations are quite user-friendly, which makes it convenient not only for the professional electricians but for the laymen as well.

Final Words

Auto-ranging multimeters make up for a note-worthy choice for the electricians, engineers, and newbies as well. By being highly capable of detecting and measuring the various electrical parameters with high efficiency and precision, multimeters are highly adaptive. 

After assessing the Klein mm400 review, we can conclude that this auto-ranging multimeter is worth every penny. Crafted as a highly sturdy electrical gear, this auto-ranging multimeter is full of striking features that are extremely useful in determining the electric ranges.

By flaunting the finest features such as a CAT III @ 600V safety rating along with auto-shutoff and battery level indicator, this device is an astonishing one.

Another notable point is that this auto-ranging multimeter works well for the standard electrical work requirements. This implies that, in terms of superiority and speed, this device manages to fulfill the criteria.

If you are a tech-savvy person and are looking for a great and affordable tool for electrical range detection, then the Klein mm400 is the best pick for you.

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