Klein CL120 Review

Editor Rating: 4.5/5

Great Product

Klein CL120 Review

Reviewed by: Timothy Henderson

Last modified: May 27, 2023 @ 11:12 am

  • Design
  • Functionality
  • Price

Klein Tools CL120 Review Summary

Stripped back to the bare essentials, the Klein Tools CL120 is a pocket-friendly clamp meter that may appeal to the enthusiastic home user and light-project professional.

Non-contact voltage alerts you to live wires without having to touch any circuitry, boosting safety for the novice operator — while auto-ranging permits clamp meter newbies to wield the unit with little-to-no knowledge of electrical metrics.

Its CAT III rating permits the tool to be utilized in three-phase environments and adds a reassuring level of protection. Additionally, memory hold and max reading features deliver enhanced practicality, allowing you to scrutinize your results long after you’ve finished testing.

A backlit LCD screen permits you to operate the unit in dimly lit conditions without the use of a secondary light. And, boasting both a low-battery alert and auto-shutoff, the risk of your machine failing mid-project due to lack of juice is minimized.

This machine comes from the Klein Tools stable — a reputable US brand with over a century’s experience in equipment retail and manufacture. The CL120 unit is the entry-level tool in its clamp meter range.


  • Weight – 11 ounces
  • Voltage – 600 volts
  • Current – 400 amps
  • Safety Rating – CAT III


  • Auto-ranging.
  • Includes a carry case.
  • Integrated testing lead holders.


CAT III certified.
In-built testing lead holder.
Memory function.
NCV detection.
Arrives with 3 x AAA cells.


Lacks TRMS technology.
No temperature measurement.
Unsuitable for mains utility wiring and transformers.

Features and Benefits of the Klein CL120 Clamp Meter

The Klein CL120 is undoubtedly a no-frills affordable machine — but does it still have sufficient versatility to suit the keen DIYer and light contractor? Stick with me as I delve into the features of this basic clamp meter.

Non-Contact Voltage Detector

A reassuring characteristic for the inexperienced home user and time-pressed light contractor. Non-contact voltage detection — or NCV — alerts you to the presence of live wires and circuits, without making contact with your target.

If the jaws of the Klein Clamp Meter CL120 are positioned in close proximity to active voltages, the unit warns you with a visible LED light and audible beep. This dramatically elevates safety — reducing the risk of accidental shocks and short circuits.

CAT III Safety Rating

Although the CL120 Klein clamp meter is a no-frills machine, it still boasts industrial-grade capabilities. With CAT III certification, not only is this machine suited to testing standard home single-phase circuits and equipment, but also to scrutinize the higher loads present in three-phase systems.

I suggest, therefore, that this unit will prove attractive to the light contractor, having the versatility to be utilized in factory environments. Should you want to learn more about the importance of CAT ratings for multimeters — check out my What Is CAT Certification article.


This intelligent system automatically adjusts the readout display to tens, hundredths, or thousandths — depending on the most suitable metric for capacitance, frequency, voltage, or current.

Not only does it permit electrical newbies to confidently operate the clamp meter, but also ensures that the more experienced pro doesn’t spend needless time fiddling with dials and switches — saving valuable work time.

Memory Hold and Max

Testing electrical circuits is a genuine hands-on experience — typically you find yourself wielding not just the clamp meter itself, but also a pair of testing leads. This restricts your ability to record readout details for scrutinization, as you have no spare digits to use a pen and paper.

Therefore, it’s pleasing to see that the CL120 from Klein Tools features a memory hold and max feature. This stores your most recent test results, while also informing you of the maximum current or voltage peak reached.

Testing Lead Holder

The Klein CL 120 arrives complete with two lengthy testing leads. While generously sized, allowing you to operate at a significant distance from the base unit — the problem arises with what to do with these probes once you’ve completed your circuit investigation.

Thankfully the design boffins at Klein anticipated this issue and created side-mounted holders for the investigative leads. Not only ensuring that these crucial components aren’t lost during downtime, but also shielding them against damage in busy toolboxes.

Backlit LCD Screen

You aren’t always going to be testing circuits in ideally illuminated conditions. Troubleshooting electrical issues can take you to less than perfect, dimly lit, environments — such as in attics, underneath floorboards, and in basements.

Pleasingly, the CL 120 from Klein boasts an LCD screen complete with backlighting — boosting readability in dark areas and negating the need for a secondary work lamp.

Battery Saving

Impressively, the Klein Clamp Meter arrives with three AAA cells, permitting you to operate the machine immediately after unboxing. The downside of these restricted-life disposable power packs is that should they fail mid-project, you could find yourself surrounded by live wiring, with no means of testing for current or voltage.

Hence, it’s reassuring to discover that the CL 120 meter has an integrated low-battery warning light, alerting you to low-energy issues. Furthermore, having an auto-shutoff system — activated when the unit is left idle — guards against unnecessary power cell drain.


As described earlier in this Klein CL120 review, using a multimeter can be challenging in the hand department — leaving you with no spare appendages. This can lead to slippage and accidents — and the last thing you want is to drop your brand new and shiny clamp meter.

Encouragingly, this device is seriously durable, built to withstand drops from up to 6.6 feet — providing you with peace of mind and protecting the internal components from unnecessary damage.

Klein Tools Clamp CL120 Meter Specifications

Klein CL120
Weight11 ounces
Jaw Size1.6 inches
Drop Protection6.6 feet
Voltage600 Volts AC/DC
Current400 Amps
Highest Safety RatingCAT III
Size8.45 x 1.5 x 3.5 inches
Batteries3 x AAA
Auto-Power OffYes
Non-Contact VoltageYes
Resistance20 MΩ
DC Polarity IndicatorYes

What Do Users Say About the Clamp Meter Klein Tools CL 120?

For me, the Klein Tools Clamp Meter CL 120 is a straightforward and easy-on-the-wallet unit that will appeal to casual and intermediate DIYers together with light contractors.

However, with limited hands-on experience of this unit, it’s possible that I’ve under or overestimated the capabilities of the machine. Therefore, to guarantee a completely thorough examination, I researched the testimonials of CL120 owners.

Pleasingly, the majority of users offered the same opinions as me, and gave the tool positive reviews. Contented owners of the clamp meter welcomed the fuss-free auto-ranging system, applauded the industrial-grade CAT III certification, and praised the safety-boosting non-contact voltage feature.

Naturally, the unit didn’t please everyone. A few guys were disappointed that the tool lacked accuracy-elevating TRMS technology, whereas others complained that the omission of temperature testing made it unusable for HVAC applications.

That said, all owners agreed that the CL 120 Klein Clamp Meter offered straightforward operation combined with durability — and at a pleasing price point.

Alternatives to The Klein CL 120 Clamp Multimeter

It’s possible, like a few of the guys mentioned above, you’re not overly impressed with the CL120 from Klein. That being the case, I’ve sourced three alternative units that may be more applicable to your demands and the needs of your DIY or trade projects.

Klein Tools CL380

If your heart is set on a DIY-grade and sub-$100 Klein clamp meter, but are disappointed in the lack of precision in the TRMS lacking CL120 — check out this machine.

The CL380 hails from the same respected Klein stable, and, like the CL120, boasts auto-ranging, non-contact voltage detection, and data hold. However, with an integrated TRMS system, it offers more accurate troubleshooting than its standard RMS cousin.

  • Slightly higher price point than the CL 120.
  • No LCD backlight, a feature of the CL120.
  • At 8.3 ounces, it’s three ounces lighter than the CL120.

Extech MA445

Should you be chasing an affordable clamp meter, yet demand a temperature testing feature that’s not a characteristic of the Klein machine — consider this Extech model instead.

The MA445 includes a detachable thermoprobe, permitting you to investigate heat levels up to 1832 degrees Fahrenheit. This may make the unit significantly more suited to HVAC and automotive users than the Klein example.

  • Comparatively priced to the CL120.
  • Unlike the Klein model, the Extech includes a backlit LCD screen.
  • CAT III certified, as is the CL120.

Klein CL800

If you’re an electrical pro who finds yourself in seriously high-energy requirements, the CAT III rating of the CL120 may be insufficient. That being the case, take a look at this higher certified unit.

The CL800 is a CAT IV machine, permitting the unit to operate in more hardcore environments such as pole-to-pole wiring and utility transformer boxes — impossible with the CL120. Furthermore, boasting a low-impedance mode, it eliminates ghost voltages — an inability of the CL 120 model.

  • Harder on the bank account than the CL120.
  • TRMS tech, not a feature of the standard RMS CL 120.
  • Rated to 1000 volts, in contrast to the CL120’s 600 volts.


Back-to-basic operation, yet with reassuring durability and CAT III industry-grade certification — the CL120 would suit the casual to keen DIYer and light contractor.

Non-contact voltage detection delivers reassuring safety, while its 6.6-foot drop protection adds impressive robustness. Auto-ranging technology permits use by clamp meter newbies, while memory hold and max functions permit effortless readout scrutinization.

Admittedly, for hardcore professionals, the machine could be lacking. No temperature testing facility and restricted to 600 volts — the clamp meter will prove unusable for HVAC engineers or mains-utility testers.

However, for the enthusiastic home user, light project tradesperson, or as a backup machine for experienced electricians — the budget Klein Tools CL120 is worth checking out.

The Klein Clamp Meter CL 120 Multimeter FAQs

Q: Where Can I Buy the Klein Tools Clamp Meter CL120 Multimeter?

Focusing on the home user and light contractor, the Klein CL120 offers CAT III certification, auto-ranging, and non-contact voltage detection. You can purchase the CL120 unit by clicking here.

Q: Where Can I Find the Klein Tools Clamp Meter CL 120 Manual?

The official Klein Tools website stores a multitude of user guides and instructions for its machines — both past and present. For rapid access to the Klein CL120 manual.

Q: What Is the Klein Clamp Meter CL120 Price?

The CAT III-rated Klein CL 120 is an affordable clamp meter available at a sub $100 price point. To check out the current cost of the Klein CL120.

Q: What Batteries Does the Klein MultiMeter CL 120 Clamp Use?

The CL 120 from the US-based Klein Tools brand utilizes three AAA power cells. Encouragingly, these batteries are included with the unit purchase — as are a soft carrying case and testing lead probes.

Q: Does the CL120 from Klein Tools Measure Temperature?

No. As a back-to-basics unit, the CL120 clamp meter has no temperature testing facility. If heat measurement is something that’s crucial in your equipment, I suggest checking out the Klein CL800.

Q: Does the Klein Tools Clamp Meter CL 120 Have TRMS Technology?

No. The Klein Tools CL 120 is a standard RMS clamp meter. If you need a testing machine that possesses accuracy-boosting TRMS tech, I recommend taking a look at the Extech MA445.

Q: Can the Klein Clamp Meter CL 120 Test Voltages?

Yes. The CL 120 can test voltages up to 600 volts. Additionally, it can also examine continuity, resistance, current, and frequency.

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