Home & Office
Why you can trust ZDNET : ZDNET independently tests and researches products to bring you our best recommendations and advice. When you buy through our links, we may earn a commission. Our process

'ZDNET Recommends': What exactly does it mean?

ZDNET's recommendations are based on many hours of testing, research, and comparison shopping. We gather data from the best available sources, including vendor and retailer listings as well as other relevant and independent reviews sites. And we pore over customer reviews to find out what matters to real people who already own and use the products and services we’re assessing.

When you click through from our site to a retailer and buy a product or service, we may earn affiliate commissions. This helps support our work, but does not affect what we cover or how, and it does not affect the price you pay. Neither ZDNET nor the author are compensated for these independent reviews. Indeed, we follow strict guidelines that ensure our editorial content is never influenced by advertisers.

ZDNET's editorial team writes on behalf of you, our reader. Our goal is to deliver the most accurate information and the most knowledgeable advice possible in order to help you make smarter buying decisions on tech gear and a wide array of products and services. Our editors thoroughly review and fact-check every article to ensure that our content meets the highest standards. If we have made an error or published misleading information, we will correct or clarify the article. If you see inaccuracies in our content, please report the mistake via this form.


Stop! Your Apple charger may be a counterfeit, and this tiny gadget can tell

This USB-C tester is like a mini-computer that tells you the good, the bad, and the ugly about your charger.
Written by Adrian Kingsley-Hughes, Contributing Writer
ChargerLab's Power-Z KM003C USB-C meter

ChargerLab's Power-Z KM003C USB-C meter.

Adrian Kingsley-Hughes/ZDNET

USB testers have gone far beyond just testing the output voltages and power of ports, and can now test and check for counterfeit Apple chargers and cables.

I have dozens of different testers, but undoubtedly the most powerful is ChargerLab's Power-Z KM003C USB-C meter.

Also: This is the ultimate iPhone car charger, and I just fixed its biggest problem

This can tell you anything and everything you need to know about a USB-C port, cable, or charger. 

View at Amazon

ChargerLab's Power-Z KM003C USB-C meter tech specs

  • Size: 1.44 x 1.4 x 0.34 inches (36.5 x 35.5 × 8.7 mm)
  • Weight: 16.5g (0.58 oz)
  • Screen size: 1.54 inches
  • Typical operating current: 15~50mA
  • Processor: ARM Cortex-M4 192MHz
  • Backup power: Supercapacitor 

The Power-Z KM003C features a 1.54-inch 240 by 240-pixel IPS color display, and can carry out a range of tests, including voltage/current detection, capacity/energy test, USB-C E-marker identification, protocol test, and more.

Also: This $30 USB-C cable includes a surprisingly awesome feature

Everything is controlled using four buttons, which is a lot easier than some of the other meters I've seen that have a bewildering array of rotating dials and tiny click switches on them. I often find I'm wasting a lot of time trying to figure out how the meter works, randomly jabbing at buttons and flicking switches.

Just four buttons on the Power-Z KM003C make it much easier to control than many cheaper meters

Just four buttons on the Power-Z KM003C make it much easier to control than many cheaper meters.

Adrian Kingsley-Hughes/ZDNET

There's USB-C in and out, and a port for connecting to a PC or power source. The ports are good quality, too -- sometimes these meters are kitted out with poor-quality components. The last thing I want is to be connecting devices to poor-quality USB ports that could cause damage.

Also: The best portable power stations you can buy

The screen is also big, clear, and easy to read. I can switch between a number of color schemes, and it rotates automatically thanks to a built-in gravity sensor, allowing me to see the readout no matter what the orientation.

USB-C tester showing a chart of the power outputs from a charger

The Power-Z KM003C can chart power outputs.

Adrian Kingsley-Hughes/ZDNET

In addition to all the power and protocol information that this meter can deliver, two features that I really like are its ability to detect genuine Apple chargers and read the E-Mark chip in USB-C cables

The JPower-Z KM003C is very good at spotting real -- and fake -- Apple chargers and cables

The JPower-Z KM003C is very good at spotting real -- and fake -- Apple chargers and cables.

Adrian Kingsley-Hughes/ZDNET

Built into the Power-Z KM003C is a supercapacitor that acts like a short-term battery, allowing the unit to continue to run for a few seconds even when disconnected from power -- a handy feature!

At $110, the ChargerLab Power-Z KM003C USB-C meter isn't cheap. In fact, that's a premium price for a USB-C meter. However, this is a quality, well-made, functional meter that I find is a cut above the rest, and offers up features that you don't see on cheaper testers.

Also: How to protect your data with a USB condom

And if you buy a lot of Apple chargers and cables, this tester can be worth its weight in gold for weeding out any counterfeit products that unscrupulous sellers might try to foist on you.

The Power-Z KM003C is a great device for making sure you're not being ripped off when buying an Apple charger online

The Power-Z KM003C is a great device for making sure you're not being ripped off when buying an Apple charger.

Adrian Kingsley-Hughes/ZDNET

If you'd rather go for something a bit cheaper, then the ChargerLAB Power-Z AK001 might be a better choice. This device is essentially a USB-C-to-USB-C cable with a power meter fitted in the middle, and has a more palatable $30 price tag. 

Editorial standards