Strong Carabiner

Here is ergonomically curved carabiner. Stronger version is b8. b7 version scaled down to 80% makes a good key ring.
This FDM gate concept was first released on thingiverse by ddf3d.com. The basic idea is the same as a standard wire gate, climbing carabiner. There are two different pivot points that create a spring action.
No branding here and Solidworks files are included.
Printed with 7 perimeters for strength. See image of pla b8 version holding a 40 lb car battery. Don't use for critical applications.