These are robust sister clips (also called brummel hooks) designed for sailboats trapeze to connect to the bungee, for ropes up to 5mm. But of course those sister clips can be used for all other purposes too. Depending on material and print setting, they should hold 10 to 50kg of load.

The picture shows prints using Carbon reinforced Luvocom PAHT filament, so that version did withstand a test with a 35kg counterpart easily, so I assume these carbon reinforced clips hold weight of up to 50kg.

A PETG version broke at approx 25kg load.