MM500 Auto-Ranging Multimeter Review

Easy-to-use, super tough multimeter that measures up to 750 volts AC and DC, resistance, and continuity


MM500 Auto-Ranging Multimeter

If you're looking for a bare-bones digital multimeter that's super easy to use, has an excellent display, is as rugged as hell, and costs about the same as a 24 pack of beer, then the Klein MM500 might just be the ticket. While the MM500 comes with a lot of good features, what really sets it apart is a simple three-button interface that automatically detects AC or DC voltage.

The MM500 is a bare-bones multimeter - it comes with the meter, a pair of 40" leads, two AAA batteries, and a very basic instruction booklet. At only 3" wide and 5-3/4" long I found that it fits easily enough into a tool belt or tool bag. However, if you have the habit of tossing tools into an open tool bag or box, then you might want to purchase the optional carry case, which will protect the display from damage.

Comes with 40" leads
Fits nicely in the hand
The meter has a contoured shape that fits nicely in the hand. I really like the size, feel, and overall design. The casing seems very durable - Klein has designed the casing (and the internals) so that the meter will withstand a drop of 10 feet onto concrete without damage. The case also has an IP67 protection rating, which means the meter internals are totally protected from dust, and it can withstand immersion in water up to 3 feet deep.
The MM500 measures AC/DC voltage up to 750 Volts, along with resistance and continuity. It also meets CAT IV 600V safety standards, which means it protects you from voltage spikes up to 8000 Volts. Plus, it includes auto-ranging (so you don't have to dial in the correct measurement value range), auto hold (which locks the measurement on the display), auto power off (which turns the meter off after 30 minutes of inactivity), and low battery status (so you know when to replace the batteries).

4000 count backlit LCD display

I found the screen on the MM500 very readable under most lighting conditions. Contrast on the 4000 count display is very good, 
regardless of the angle at which you look at the screen. In less than ideal lighting conditions the backlit screen does an excellent job of illuminating the display. However, it puts a real strain on the batteries, so you'll want to use it judiciously.

When powered on, the meter defaults to AC mode, but as mentioned earlier, it automatically senses when you measure DC voltage. The screen always shows 'Apo' (Auto power-off active) and AT (Auto range active). The auto power off function can be easily disabled.

Easy to use control panel

There are only three buttons on the control panel, so it's pretty easy to remember what it is they do. The buttons are large, easy to depress, and the labels are easy to read. The A-Hold button turns the auto hold feature on or off. When activated, the auto hold captures and displays the first stable value until a new stable value is measured. The A-Hold button also serves to switch the back light on.

The middle button selects the resistance/continuity mode, while the bottom button selects voltage mode. Depressing either of these buttons powers-on the meter, while holding either of them down for a couple of seconds powers-off the meter.

No lost screws

The battery door incorporates a thoughtful design feature - captive screws that won't fall out when you unscrew the cover.

Self-storing leads
Leads are extendable
A clever feature is that the test leads can be stored on the back of the meter, which protects the tips from damage. The leads can also be extended to make it easy to test receptacles one-handed.


The MM500 has to be the least complicated multimeter on the market. It makes quick work of measuring voltage, resistance and continuity, meets CAT IV safety standards, has an excellent display with easy-to-read digits, and a set of basic features - all for under $60. That says excellent value for the money. However, I'd like to know how you think the MM500 compares to your (non-True RMS) multimeter.
  • 1-1/4" x 3" x 5-3/4''
  • 1" x 1-3/4" backlit 4000 count LCD display
  • 6 oz weight
  • 750V reading, AC and DC
  • Detects AC or DC voltage automatically
  • Resistance range of 4000 ohms
  • Sampling frequency of 3 samples per second
  • Visual and audible continuity indicators
  • Auto ranging
  • Auto hold
  • Auto power off
  • Low battery indicator
  • CAT IV safety rating for 600V
  • IP67 protection rating for dust and water
  • Battery door has 4 captive screws to eliminate lost fasteners
  • Self-storing leads
  • Includes: Test leads, 2 AAA batteries
  • 2 year warranty

COMPANY:Klein Tools
SOURCE:Dealer Locator
Carl Duguay, October 2013

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