This is a hook to be glued to the underside of for example a table to guide single cables. I use them for my electrically adjustable table as the old hooks where falling off. You need some proper tape like 3m 5952 or other tapes that can handle to stick onto plastic properly and long term.

The inner diameter is 9mm. Cable needs to be at least 4mm thick to not fall out.

Use filament that can take some flexing like ABS, PETG or Nylon however if you take Nylon beware that you most likely need special tape to stick to it. PLA might work however it could be too stiff. Did not try it.