There are, at a conservative count, eleven USB-C chargers in this house, and every single one of them claims to be fast. Some of them are lying. Not maliciously — optimistically, the way a gym membership is optimistic. And until recently I had no way to tell the honest ones from the ones that quietly give up the moment something asks them for real work, so I did what everyone does: plugged things in, waited, and got mildly annoyed at nothing in particular.
What the thing actually is
The WITRN CC1 is an inline USB-C power meter, which is a long way of saying it is a small red rectangle you put between the charger and the thing being charged. It then displays, on a little color screen, what is genuinely happening in there — volts, amps, watts, and what the two ends actually agreed to give each other. It speaks PD 3.1 and reads up to 28V, which covers essentially every USB-C brick, power bank and laptop charger you are likely to own, and a few DC supplies you probably wired yourself and should not talk about in public.
Why this belongs on a 3D printing bench
Because a shocking amount of "my printer is being weird" turns out to be "my power is being weird." The Pi that reboots itself forty minutes into a print. The power bank advertising 100W that taps out somewhere around 30. The USB-C cable from the junk drawer that turns out to be charge-only, or charge-only-ish, which is worse. This is the same argument I made for the multimeter, just pointed at the USB-C half of the bench, where nothing is labeled and everything insists it is fast.
The nice part is how quickly it converts an afternoon of guessing into a number. Plug it in, look at the screen, know. I have already used it to demote two chargers to "phone only" and to discover that my favorite braided cable has been silently throttling everything I have plugged into it for about a year.
It is currently sitting at a clean 5.0 stars, though I will be honest that this is across ten reviews rather than ten thousand — it is a newer listing, so take the number for what it is. The reviews that are there all say the same two things, which is that it is tiny and that it works. Check it out here if you have gotten tired of taking your chargers at their word.