A clip-on castor wheel mount for the Ikea Algot frame. Fits standard castor stems (7/16"), and snaps on to the horizontal bars at the bottom of the frame.
Attach with the longer arm on the bottom so that the weight of the shelves tends to keep the mount clipped on, instead of detaching it.
I printed this with 4 perimeters, 0.2mm layer height, 15% infill on a Prusa Mini.
The author hasn't provided the model origin yet.