Amazon lists this as incompatible with Colorados but it fits well on my 2020.
Just came in today:
At first the key had a hard time coming out but it sits well and works as needed, used best as a deterrent since it is just plastic and will keep debris out.

Otherwise I am happy with my purchase.

A bit difficult to put on and remove the key but it stays on firmly. Not sure if it'll come off easily like it was shown in a previous review but it's a basic/simple deterrent. It's cheap plastic so I hope it lasts a while.

I wanted something as a deterrent and more or less just something to keep water / dirt out.
I noticed when I get gas, after or during rain, a couple drops of water lay on the inlet to the gas tank. By design the flap over the opening keeps things out but when you stick the fuel pump nozzle in the inlet, the flap opens and that little bit of water goes in the tank. (Not a big deal.) This cap prevents that and also acts as a deterrent to vandals etc. as it appears to be locked. I said appears because I can pull it off even when it looks like it is locked on. so I gave it a 4. To be fair, Chevrolet says it is "Capless Fuel Fill" and this cap isn't even supposed to fit. There isn't even supposed to be a cap for the 2019 Silverado LD. Locking and unlocking is a little hard because there isn't a lot of room for the key and your fingers inside the opening. Also the key won't come out of the cap unless it is in the locked position. It works for me, but like I said, the truck is designed to be capless.

99 percent plastic

Installed on a 2022 Buick enclave works perfect nice fit!