These are hooks for the IKEA SKÅDIS boards. Unlike others I have seen these are made to snap in to the board and won't come loose or wiggle around.

I am making models with different hook lengths available here, from 10 mm to 50 mm in 5 mm increments.

Some slicing and printing optimisations:

• I got good results with a 0.4 mm nozzle and 0.1 mm layer height.

• I print the hooks “lying down” on their side.

• Since there are some round fillet overhangs I enable supports.

• In order to have the strongest hook possible I want to have 100% infill, and all the print lines aligned with the shape of the hook. Usually the 100% infill is a rectilinear pattern, which I think won't be as strong. In order to have the lines of plastic aligned with the shape of the hook I increased the number of perimeters such that the entire print will consist of perimeters. In Prusa Slicer: Print Settings → Layers and perimeters → Perimeters.