This is a 3D printable Carabiner to be printed in two parts. It can be printed from about 80% scale to 125% scale for different sizes. At first it is a little challenging to get the spring into the carabiner but it does work. Just slot the oval into the oval and get that to click into place then move the arm to behind the latch and then push the slanted pin over the wall and into the slot.
I have been printing at 80% infill but does work with less - I would only recommend going down to 50% minimum but its up to you. Use ABS or stronger filament to last long however PLA does work but after a while may stop springing back.
This has two parts, the bottom section is for keys and keyrings then the top is to connect and attach to where ever .