This hook is used to attach 1" webbing to a fixed point. The fixed point should be a small sewn loop of 1" webbing. It works just like a normal "ladder lock" style adjuster, except the fixed end is easily and securely removable.

This type hook is usually made of steel (a la ITW G-Hook) or aluminum (a la Metolius Crash Buckle). The ITW version is very heavy, and the Metolius is reasonably priced, but impossible to find with reasonable shipping. You can find these inexpensively if you buy in bulk from alibaba.

I plan to plasma cut this from aluminum as a first go, if that fails, then I'll mill it on a small cnc. Some things will need adjusting to mill with an 1/8" bit, though.

After it's cut, it should be bent like the metolius buckle to increase the locking power. https://www.metoliusclimbing.com/crash_buckle.html