ChargerLAB Power-Z C240 Portable USB-C Tester, Digital Power Meter, Supports up to 240W and PD3.1 QC5.0, for USB-C Phones, Laptops, Chargers and More

This is about as simple as it gets. Plug the monitor inline with your device and see how much power you're using in watts, amps, and volts upto 240 watts (the current maximum). Cumulative energy delivered in watt hours is also displayed. This information can be used to verify that your cell phone is charging at its maximum rate, or that your power supply is providing enough power for your computer to charge. If the display is off, no power is present. Did you plug in your power supply? Is it broken? Is the cable good? These questions can be answered with this simple device. It comes in a nice tin box for easy storage and protection.

Good product and worth every dollar. Buy it

I only have one small gripe with this - it's SMALL. Maybe it's my eyes but don't expect to read the small print unless you have a magnifying glass, but outside of that it's plug and play. USB3/USB-C is wildly different than USB2 - and the plug type is now not just on chargers but on so many devices. Unfortunately the cable guys are allowed to sell cables lying about their specs, missing channels or features which in the end means you won't get the performance the cable claims to have. With this you can see if the cable even allows USB C charging, meaning does it have the wires between your charger and the device to charge, so the right power can be offered to fast charge. In most cases it's the cable - cheap cables are cheap for a reason; they may work great for you but don't blame the charger if it's slow. And this little device can tell if that's the case. It's not in the cheap end, but if USB C is what you do, it's where you should begin. I've seen other power-z units with similar features - not just on AMZ that may have better displays and additional cable verification features. This is the base model and works great.

I REALLY like this little meter. Accurate enough for what I want, which is to just generally see what's going on with my devices/cables. This is plug-and-play - no settings to adjust but rather a simple power monitor. Form factor and cosmetics are great - but note this is a SMALL device, and along with it a small (but really nice) display. Build quality and fitment are excellent. Has a solid feel and some weight to it. The IPS display is bright with excellent color and resolution. My only concern is that the screen display does not come covered with a protective peel-off film to protect from scratches. It really should, but mine came in perfectly fine though...

Handy to check how much power a USB device is consuming, but when combined with a wall adapter, this little thing can even be used to see if a wall outlet is able to pump out at least enough proper power for standard USB power (5V === 1A) if not more (since USB-C supports higher amounts of power) as well as just see how much power something like a power bank or my iPad can output. Really, it's just fun to test it out with different stuff to see what readings you get.

TL; DR: well built unit good to look at charging processes only. cannot be used inline with a data device. The unit is a well-built small dongle with a bright screen that is very legible. The typeface used is small, but this is inevitable due to the small screen size. It does what the listing shows. However, when connected, data does not seem to flow in either directions, or if it does, something is preventing establishing a reliable connection. This means that you cannot monitor USB SSD drives, or check how the PD function of USB docking station really works, because the laptop cannot access any of the devices connected to the dock -- and therefore cannot be monitored while using such devices. I did not expect the device to provide any information regarding data flows; such functions are not in the specs after all. However, I did not expect that the unit would interfere with data communications. Bottom line: great unit to monitor the charging function of a device... but that's it.

It may not be very accurate, but it is accurate enough. It is also very simple to use. If you want ultra accuracy, buy Power-Z KM003C.

This meter works well and is easy to read. Handy to tell if your device and charger are really fast charging. It is kinda expensive though. It does seem to pass data between my iPhone and the charger as I can watch the current ramp up over time.

Great device. With this I can see the power consumption of my ESP32 devices as well as charging power of my laptop and every device in between.

it works

Works as well as advertised

I suspected motherboard damage but this awesome tool let me know it was a bad power supply. Easy to use and works great.

Do NOT bother with this item. It's a simple device and priced at a significant premium to similar devices so you expect a reasonable degree of accuracy - but it's absolutely miles out. Wish I'd read the other 1* and 2* reviews first! The seller must surely be aware there is a problem but when contacted was unhelpful. Functionality - very simple compared to others. Accuracy - very poor. Readability - decent screen but does not rotate so annoying. Value for money - zero.