Review on USB-C Extension Cable, Fasgear 6ft USB 3.1 Gen 2 Type-C Male to Female Cord 10Gbps - 💻 Supports 4K Video and Audio Output - Compatible with Thunderbolt 3 Port, MacBook Pro, Dell XPS, Switch (1.8m, Black) by Patrick Matin

I tested them for power and dual monitors (with a USB-C dock). and they seemed to work fine (I didn't notice any difference in video quality with or without a cable. However, no USB devices (keyboard, mouse, etc.) worked...). The computer did not see the device at all (there were no assembly noises, errors, etc.). The assembly quality of the plugs seemed high. I bought two cables and both had the same problems. I can only guess which one - somehow the signal cable wasn't properly connected through the cables, but I don't know enough about USB-C to test it or say what it was (maybe just extension cords?) which I don't know about knew. They're usually fully reversible, but it turns out that older USB 2.0 devices only require the cables to be plugged in one way. I don't know why, but after playing around with reversing the connections on the power strip, I was able to get everything working with these extension cords (the "spare cord" I bought from another company and had a "READ ME FIRST" note explaining I may need to replace the plugs). So after replacing the cables they work fine so I added the missing stars.