So recently I've been thinking about putting my hot wheels on a keychain to hang on my bag. But most people just drill into their cars. That wasn't an option for me as I don't have a drill at home and I didn't want to ruin a hot wheels car. So I came up with this. Almost all hot wheels cars have the same distance between the faces of the wheel, because they need to fit on the tracks. Based on that knowledge, I modeled this adapter that should fit most cars. It snaps on to the rear axel, and it holds on pretty well. I printed mine in PETG so it is a stringy mess but your results may differ.