This is pretty simple and possibly silly. These are just replacement Valve Stem caps with the TRD logo on top. I originally got the ideas from the G3Ek's design: https://www.thingiverse.com/thing:2611174. I even printed it a few times trying to make it work.

It was a bit frustrating removing supports at first, but I got the hang of it. But, they were loose. And I felt that the top-hat brim was unneeded. I was going to remodel it, but I decided to just design a new one from scratch. Still, i appreciate his work and creativity. Thanks, dude!