I currently have the one size hook, I'm thinking about printing different sizes but haven't done so yet. The parts that hook into the pegboard are round and designed for the standard US 1 inch pegboards. I have the DeWalt workbench with a metal pegboard mounted on the back. The pegs are 5mm diameter.

Prints flat with no supports.

*This looks very similar to the pegs from the Universal Peg Board Peg System and that is because after remixing a number of files for that system I took my own dimensions and created this hook from scratch.