A better locking carabiner!

Features

• Threading on both sides of the latch.
• Snug clearances so that the latch and nut don't feel loose.
• Stoppers on both sides of the nut to limit its travel.
• The latch is print-in-place.
• 8 mm thick for stiffness and strength.
• Obviously not intended for climbing. It should be fine for attaching things to your bag, hanging lamps in your tent, as a keyring, etc.

Printing

• I suggest using or modifying the provided print profiles. I've set it to print per object and used a brim to prime the flow before each object starts. Otherwise the nut might have bed adhesion issues.
• I suggest using arachne walls to reduce stringing between the threads.
• No supports needed, the latch is printed in place.
• It might initially be tough to break the latch free. If so, gently bend or twist the print along the layer lines and you'll hear a faint snap as the top of the latch breaks free. Then gently push the latch inward to free it around the pivot point. Different filaments might expand at different rates, so it might be more or less snug for you. I found PLA to be fine and PLA silk to be a bit tighter.
• The model was designed around 0.2 mm layer heights.

Let me know how the prints turn out! Enjoy!

PS. I've provided the Fusion and STEP files if you want to edit it for your own needs.