Got a used HP Probook laptop. Just needs a new drive. HP specs say it has an m.2 2280 slot. So that’s what I ordered. Guess I needed to look closer.
edit: Thanks for all the info, guys. Different types of keys are explained here. Gonna have to look for a sketchy no-name brand.
You COULD have gotten a 2230 which is smaller, and gotten a 3d printed filler part to fill the space. I did that with one of my laptops because the 2242 is a pain to find.