Twist-lock hooks for ierting into the groove of a roofnest roof-top tent (i.e., an M8 channel groove). Friction fit. Add perimete and infill for strength; the thin hook is <6mm diameter to accommodate most tarp grommets, but not that 6mm of PETG isn't that strong for tarps in the wind. Suggested uses are more for hanging lanter and similar. Intended for temporary quick-iquick-out itall; not permanent attachment. Recommend PETG for UV resistance.