Spacer to help with flooring install, drywall, subfloor, wherever you need to leave a space between 2 things , print without support, pretty simple.
you could also use this as a calibration test for your printer, to see if all the size is the right size using a caliper.
¼", ½", 1", 1 ¼", 1 ½"
The author hasn't provided the model origin yet.