Thanks to @ericsnis for doing all the original measuring of the hook.

However, their model was too (almost) perfect a recreation of the injection molded part.

I redesigned it to be more 3d printable, while also changing the mounting setup.

I wanted to be able to mount my leaf blower in the Elfa rack, and the leaf blower doesn't really have any handle that could fit in the friction holder. So I instead made a hook that is screwed into the back of the bracket.

Including the f3d file since @ericsnis was nice enough to do the same, and the history on this could probably be reworked a bit to make the same friction fit model, but designed to be more 3d printable. The holes are based off some random screws I had in my garage, that are roughly 3mm center bore, with 4mm threads, a 9x3mm chamfered head, and 20mm length. The f3d file should be easily modified to accommodate different screw sizes.

The design should only need to have supports on the flat part above the tabs:

(supports in green, I used prusaslicer's smart fill paint on supports to get only that flat surface supported).

I printed this in PETG with PLA support interfaces and the supports popped right out.