the knobs have a M4 thread. if printed in one piece with a color print, it might be possible to glue it on something. But i would recommend using a M4 bolt.
Printing
layer height 0.20mm
infill 20% grid
perimeters 3
The Wrench G-code is a sequential print. (To minimize travel and thus stringing)
(Print Settings > Output options > Complete individual objects)
Wrench2 has a bridge that has to be removed or by using Wrench2 without bridge you can add support instead of a bridge.
Needs Support
Doesn't need support
Alternatively you can also print it with a color change but you can't use sequential printing so you'll still have to print twice if you want two different colored portals.
The author hasn't provided the model origin yet.