KLEIN TOOLSMM420 Digital Multimeter, Auto-Ranging TRMS Multimeter, 600V AC/DC Voltage, 10A AC/DC Current, 50 MOhms Resistance

Klein Tools has always set the standard for professional-grade tools, and this multimeter is no exception. From the moment you pick it up, the build quality speaks volumes — rugged, solid, and clearly designed for real-world job site demands.Accuracy is spot on, whether you're measuring voltage, current, resistance, or continuity. The readings are consistent and fast, with virtually no lag, which makes troubleshooting efficient and reliable. The auto-ranging feature works flawlessly and saves time in the field.Durability is another standout. This meter is clearly built to last, with a reinforced casing that can handle drops and daily wear. The display is sharp and easy to read, even in dim lighting, and the controls are intuitively laid out for one-handed use.Packed with features like true RMS, backlit display, and a wide measurement range, it’s everything a professional or serious DIYer needs — without the unnecessary fluff. Klein Tools continues to prove they understand what technicians actually use and value.In short, this meter nails it: fast, accurate, durable, and thoughtfully engineered. If you want a meter you can count on day in and day out, this is it.

For auto-ranging feature with true-RMS for accuracy, this moderately priced multimeter should be able to handle most any homeowners needs along with many tradesman's requirements. While not a Fluke, Klein offers a quality meter for less than half the cost with reasonable accuracy. Auto-range can be turned off if desired.

Tool is good, working properly, delivery was so quick.

Not bad. Mid-tier capabilities with a great screen. Thinner than most full functional multimeters, side lead jacks allow for thinness, better portability without sacrificing safety or ability to change leads. As capable as my Fluke 117 but 1/3 the price and easier to pack. I would consider this to be the perfect back up to my Klein 810 Pro or for standalone use in a quick troubleshooting scenario. Nit picks include position of lead jacks right where my fingers hold the meter; lack of non-contact voltage sensing and a lack of a work light. Any two of those three would make it a 5/5.

A friend gave me his Klein MM 1000. He is an electrician. It was pretty beat up and have been used for many years in a tough environment. I was really impressed with the capabilities of it. However the switch eventually gave up.I wanted to find something similar and was pleased to find the client MM 420. It can "only" deal with up to 600 V circuits, which is not going to be a problem for me. It measures all the important electrical requirements and also includes temperature with an included thermocouple.I bought this one because the display looked really nice, and it is. They changed the LCD color and it really stands out, especially when backlit.Klein multimeter are "bench tested." I put this in quotes because this particular bench test means that they can handle a 3 foot drop off of a bench.I have been happy with every Klein tool I've ever bought. They offer excellent quality at very competitive prices. You can buy very basic all the way up to professional. The fact that my friend, who has been a career electrician, uses Klein multimeter was certainly a plus to me.Very happy with this purchase.

The media could not be loaded. DIYer ESSENTIAL. There are a LOT of bits and should cover almost all DIYer situations. No issues except the bits come loose from their friction fit slot.PROS✅ Klein = Awesome✅ Comprehensive - AC/DC voltage, AC/DC current, resistance, frequency, temperature✅ Durable - rugged, drop-resistant housing. Meets specific safety standards also.✅ Display - bright backlightCONSNone!TIPS💡 Storage - it’s a piece of sensitive equipment. Store and treat it with care.💡 Multimeters can seem scary to a DIYer - watch some youtube videos!

I've been a fan of Klein Tools for years, so considering a Klein multimeter wasn't difficult at all. I've used mostly Fluke multimeters in my 40+ year carreer as a technician. They are considered the best of the best. With that accuracy, repeatability, and quality, you pay dearly! So I was looking for a second lower-cost meter. I was also looking for a reverse backlit display--white numerals on a black background. I'd looked at Milwaukee, but they do not include a diode check function. I chose the MM450 for it's features and price point. While I have not compared accuracy to other meters, published specs are similar to other more expensive meters. There is one minor issue in my review, and that is the white-on-black display needs to be viewed pretty much head-on for best quality. Depending on the tilt angle, there are positions where the display is very faded, almost to disappear. That might be an issue if you measuring in tight quarters or not able to look straight on otherwise. It comes with test and temperature probes, and fabric case. An optional rare-earth magnetic hanging strap is available. Besides voltage and current, it also measures resistance, capacitance and frequency, along with a peak hold function, making it an ideal meter for most service techs.One other minor detail...when in Auto scale mode, it can take up to 5 seconds for the reading to finally resolve. If you are troubleshooting something point to point and in a hurry, this may be an annoyance.However, if you turn off the Auto-scale mode, the readings display quite a bit faster. Given the display issue (and that might not be a problem for everyone) I'd give it a 4.5, if that were possible. But it's certainly better than a 4, so a 5 it is!

Between Klein and Fluke: Klein is better priced and they make decent tools.