This coat hook is based on a sheetmetal one that I made as an apprentice. The plastic one is a tad thicker for durability, with a gusset added inside the hook area. It fit my toolbox fine, but for a tighter lid it may be necessary to file it down just a bit so it is snug but not too thick. Also included is the f3d and step file so you can modify to fit your application. 

Works fine as PETG but the stiffness of PLA is more well-suited. I would say PLA is a requirement if you make it any thinner than 3 mm.