Asymmetric carabiner with internal hook. Inspired by the mas design titanium carabiners.
Printed with MadeSolid green PET+. 70mm with a 17mm gate.
Of course these are non-load bearing. If you need something strong, Trango, Metolius, Mammut, and quite a few other companies make some very nice aluminum carabiners.
The design uses gaps of 0.2mm which may fuse together with some printers/filaments. It's designed to work with MadeSolid PET+. ABS and PLA aren't flexible / elastic enough for the hinge (it will work, but the hinge will be fragile)