Klein Tools MM420 Digital Multimeter, Auto-Ranging TRMS Multimeter, 600V AC/DC Voltage, 10A AC/DC Current, 50 MOhms Resi
£320.13 inc. VAT (£266.78 ex. VAT)
- Measures up to 600V AC/DC safely for routine electrical fault-finding.
- Auto-ranging True RMS readings improve accuracy on modern electronic circuits.
- Tests up to 10A AC/DC current for checking motors, appliances and wiring.
- 50 megaohm resistance range helps diagnose continuity faults and component issues.
Why Choose OhmVolt
Built for real electrical work
The Klein Tools MM420 is a professional digital multimeter designed for electricians, maintenance engineers and serious DIY users who need dependable day-to-day readings. It combines true RMS measurement with auto-ranging convenience, making it a practical choice for fault finding, installation checks and electrical troubleshooting across domestic, commercial and light industrial settings.
Core functions without unnecessary complication
This 600v digital multimeter covers the measurements most users rely on most: AC/DC voltage up to 600V, AC/DC current up to 10A, resistance up to 50 MΩ and continuity testing. As an AC DC multimeter and resistance continuity tester in one compact tool, it helps reduce kit duplication while keeping testing straightforward and efficient on site.
Well suited to electricians and HVAC diagnostics
If you need a multimeter for electricians or a multimeter for hvac fault tracing, the MM420 offers an excellent all-round specification. True RMS capability supports more accurate readings on non-linear loads than basic meters, while the handheld format and clear display make it easy to use around panels, plant rooms, controls and maintenance spaces.
Trade-grade reassurance
Positioned as a dependable alternative to generic marketplace meters, the MM420 focuses on practical performance rather than gimmicks. With a clear safety-led design, robust handheld construction and trusted Klein Tools brand credibility, it is a strong choice for buyers comparing against Fluke and Megger options but seeking a capable, premium-value everyday multimeter test meter.
Technical Specifications
- 0.1mV to 600V AC/DC
- 0.1µA to 10A AC/DC
- 0.1Ω to 50MΩ
- 4000 count LCD
- CAT III 600V, CAT IV 300V
- CE, UKCA
- 2 x AAA batteries
- 165 x 82 x 50 mm
- 260g
- 2 Years UK
Price Comparison
See how our price compares across UK retailers
| Retailer | Price | Delivery | Warranty |
|---|---|---|---|
| OhmVolt UK (Specialist)BEST | £320.13 | FREE | 12 months + UK Support |
| eBay (est.) | £400.16 | Varies | Seller dependent |
| High Street RRP | £512.21 | N/A | Varies |
Prices checked 12 June 2026. Prices may vary.
Customer Reviews
I bought this for maintenance work across commercial units and it has been spot on. The true RMS readings are far more confidence-inspiring than the cheap meter I replaced, and continuity testing is quick and clear.
Arrived quickly from the UK and feels like a proper trade tool. I mainly use it for 230V checks, resistance testing and control panel fault finding, and the auto-ranging function saves time every day.
As someone who needs reliable readings rather than gimmicks, this is a very sensible handheld digital multimeter. The display is easy to read and the CAT III 600V rating was one of the deciding factors for me.
Very good meter overall and much better built than budget marketplace options. My only small criticism is that I would have liked a carry pouch included, but for voltage and continuity work it has been excellent.
I was comparing this against a Fluke model and ended up choosing the Klein. For the kind of domestic and light commercial jobs I do, the 600V range, 10A current measurement and true RMS accuracy are exactly what I needed.
I use it for HVAC fault finding, especially checking control circuits and verifying supply voltage. It has been dependable so far, though a temperature function would have made it even more useful for my kit.
Excellent value for a professional digital multimeter. It feels robust in the hand, the readings settle quickly and it is ideal for home rewiring checks, appliance diagnostics and general electrical troubleshooting.