Basic all-purpose holiday lights hanging clip. A set of 200 of these runs about $10 ($.05/clip) on Amazon or other online retailers. Depending on your print settings and what filament you use and how much you paid for them, these will run half the cost or less. These also allow you to make as many as needed and prevents waste from overbuying clips. Included profile is for 2 walls which results in firm clips with enough flex for shingles or other relatively thin applications. If you need it to go over something ticker like the lip of a gutter, either scale the clip up as needed or check out my gutter/iceicle clips here.