Klein Tools MM420 Digital Multimeter, TRMS Auto-ranging, 600V, Temp
Klein Tools' MM420 Multimeter is an auto-ranging, true root mean square (TRMS) multimeter. It measures AC/DC voltage, AC/DC current, and resistance, as well as temperature, capacitance, frequency, duty-cycle, and tests diodes and continuity. Designed exclusively for electricians, this multimeter boasts increased accuracy, a wide voltage range of up to 600V, a current range of 10A, and a resistance range of 50 MOhms. Additional features include Lead Alert protection with LED illumination, a backlit display, a low battery indicator, and a durable meter body. The Klein Tools Test and Measuring product line is the result of extensive research and input from electricians across America.
Klein Tools' MM420 Multimeter is an auto-ranging, true root mean square (TRMS) multimeter. It measures AC/DC voltage, AC/DC current, and resistance, as well as temperature, capacitance, frequency, duty-cycle, and tests diodes and continuity. Designed exclusively for electricians, this multimeter boasts increased accuracy, a wide voltage range of up to 600V, a current range of 10A, and a resistance range of 50 MOhms. Additional features include Lead Alert protection with LED illumination, a backlit display, a low battery indicator, and a durable meter body. The Klein Tools Test and Measuring product line is the result of extensive research and input from electricians across America.
Klein Tools' MM420 Multimeter is an auto-ranging, true root mean square (TRMS) multimeter. It measures AC/DC voltage, AC/DC current, and resistance, as well as temperature, capacitance, frequency, duty-cycle, and tests diodes and continuity. Designed exclusively for electricians, this multimeter boasts increased accuracy, a wide voltage range of up to 600V, a current range of 10A, and a resistance range of 50 MOhms. Additional features include Lead Alert protection with LED illumination, a backlit display, a low battery indicator, and a durable meter body. The Klein Tools Test and Measuring product line is the result of extensive research and input from electricians across America.
Klein Tools' MM420 Multimeter is an auto-ranging, true root mean square (TRMS) multimeter. It measures AC/DC voltage, AC/DC current, and resistance, as well as temperature, capacitance, frequency, duty-cycle, and tests diodes and continuity. Designed exclusively for electricians, this multimeter boasts increased accuracy, a wide voltage range of up to 600V, a current range of 10A, and a resistance range of 50 MOhms. Additional features include Lead Alert protection with LED illumination, a backlit display, a low battery indicator, and a durable meter body. The Klein Tools Test and Measuring product line is the result of extensive research and input from electricians across America.
in 35 offers
The lowest price for Klein Tools MM420 Digital Multimeter, TRMS Auto-ranging, 600V, Temp right now is $46.89 at Bunnings Warehouse, compared across 20 retailers.
The all-time low was $19.00 on 25 Apr 2026 — today's price is 147% above the lowest ever. It has been notably cheaper before — worth setting a price alert.
Prices last updated 13 June 2026.
Last updated at 13/06/2026 06:15:50
Klein Tools MM420 Digital Multimeter – TRMS Auto-Ranging, Measures 600V AC/DC, 10A Current, Temperature, Capacitance & Frequency, Lead Alert, Backlit
Free delivery
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
Klein Tools 600V 10A Auto Ranging Multimeter MM420
Delivery $10
KLEIN 600V 10A AC/DC Autorange TRMS Temp Mmeter A-MM420
Delivery between 19–24 June $13.25
Klein A-MM420 600V Digital Multimeter TRMS Auto-Ranging Temp
Delivery $16.65
Klein Multimeter Digital Auto TRMS 600V - A-MM420 - Tool Kit Depot
Delivery between 19–24 June $10
Mm420 Digital Multimeter – Trms Auto-ranging, Measures 600v Ac/dc, 10a
Free delivery
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
Klein Tools Mm420 Digital Multimeter – Trms Auto-ranging, Measures
Free delivery
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
Mm420 Digital Multimeter – Trms Auto-ranging, Measures 600v Ac/dc, 10a
Free delivery
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
Mm420 Digital Multimeter – Trms Auto-ranging, Measures 600v Ac/dc, 10a
Free delivery
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
Mm420 Digital Multimeter – Trms Auto-ranging, Measures 600v Ac/dc, 10a
Free delivery
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
originally posted on homedepot.com
I've tried a lot of different meters over the years and so far this one is great. I have a Fluke that give up the ghost and this is a perfect replacement. Has all the features I need and is a quality product for the price point. Highly recommend.
originally posted on homedepot.com
I bought this to replace an inexpensive multimeter that finally stopped working. It seems to work fine and is as accurate as it needs to be for trouble shooting household electrical problems. The continuity feature seems a little slower to signal than my old one. I have not had the issue of the voltage not zeroing like some reviewers have indicated. It is made in China but I could not justify paying 3 times as much for a Fluke meter. Klein hand tools have a good reputation.
originally posted on Ace Hardware
This meter meets all of my needs very well. I am a homeowner who likes to troubleshoot my own problems before having to call a professional. The meter is solidly built and easy to use. I also like the backlight feature for easier reading in dark areas. I have already used the temperature probe while checking out my dehumidifier. The holder on the back of the case is VERY handy for holding one of the probes and the meter in one hand while using the other probe with the other hand when you can't set the meter on something. It works as advertised! I recommend it.
| Application | Testing and Measuring Voltage |
| Batteries | 2 x AAA |
| Drop Protection | 2 m (6.6') |
| Display | 4000 Count LCD |
| Voltage | 600 V AC/DC |
Klein Tools MM420 Digital Multimeter – TRMS Auto-Ranging, Measures 600V AC/DC, 10A Current, Temperature, Capacitance & Frequency, Lead Alert, Backlit
Free delivery
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
Klein Tools 600V 10A Auto Ranging Multimeter MM420
Delivery $10
KLEIN 600V 10A AC/DC Autorange TRMS Temp Mmeter A-MM420
Delivery between 19–24 June $13.25
Klein A-MM420 600V Digital Multimeter TRMS Auto-Ranging Temp
Delivery $16.65
Klein Multimeter Digital Auto TRMS 600V - A-MM420 - Tool Kit Depot
Delivery between 19–24 June $10
I've tried a lot of different meters over the years and so far this one is great. I have a Fluke that give up the ghost and this is a perfect replacement. Has all the features I need and is a quality product for the price point. Highly recommend.
I bought this to replace an inexpensive multimeter that finally stopped working. It seems to work fine and is as accurate as it needs to be for trouble shooting household electrical problems. The continuity feature seems a little slower to signal than my old one. I have not had the issue of the voltage not zeroing like some reviewers have indicated. It is made in China but I could not justify paying 3 times as much for a Fluke meter. Klein hand tools have a good reputation.
This meter meets all of my needs very well. I am a homeowner who likes to troubleshoot my own problems before having to call a professional. The meter is solidly built and easy to use. I also like the backlight feature for easier reading in dark areas. I have already used the temperature probe while checking out my dehumidifier. The holder on the back of the case is VERY handy for holding one of the probes and the meter in one hand while using the other probe with the other hand when you can't set the meter on something. It works as advertised! I recommend it.
Bought to test the solar panels on our boat. I have a really good meter I got from my brother that is just too complicated for me to use (I'm not an electrician). This one is fairly easy to use and set to the desired reading type. I like that it says AC / DC Volts and Amps instead of just having a symbol that no one knows what they mean.
I borrowed an old digital multimeter, but then purchased the digital for Klein. Is is quite accurate. The auto-ranging makes it much easier than walking down a series of settings to find resistance. The audio conductivity indicator is also a great idea.
Great product. I was able to test my old fluorescent lights to see if they were still good. Ace employees are and have always been very helpful. They helped me get the right fluorescent tubes for my kitchen.
Echoing what many have already said, this is a feature-rich multimeter that will be suitable for both bench and field work. The supplied thermocouple is super handy and works great. The supplied probes seem more at home on the bench, and so consider buying some Klein Tools replacement probes, which I did and also recommend.
The Klien MM420 multimeter appears to be well made and is easy to use. The 420 has several features that the 400 does not have, such as the Lead Alert LEDs and the placement of the fuses, which is really nice. The dial operates smoothly.I thought the price was great for a quality product.
I have very little experience or education with electric systems, so I researched extensively. This is a great product for entry level and exceeded my expectations. i have used it 100% more than I thought I would. Very happy with this purchase!
I would give 5 stars but I have to subtract 1 for the test leads. When I first tested the leads using a continuity check on the leads themselves, I got an open circuit. I noticed the metal lead tips have a thin coating of some clear plastic on them. I used fine grit sandpaper to remove the coating. After a light sanding, they work fine. The leads are kinda flimsy too. I recommend buying a set of Fluke test leads as they fit perfectly in the lead sockets. Again the meter is a good value and works fine for light duty applications.
| Application | Testing and Measuring Voltage |
| Batteries | 2 x AAA |
| Drop Protection | 2 m (6.6') |
| Display | 4000 Count LCD |
| Voltage | 600 V AC/DC |