Shackles

[LHaven]

Originally Posted by Wmckinsey

It looks like a carabiner, but has a thread lock. Any home repair store has them. ~ $10 each or less.

You're talking about the doohickies in the first photo in post #8, right? I've always heard those called "quick links." Maybe that's only the smaller sizes.

[khb0112]

I deliver RV's for a living from Elkhart, IN to all parts of the USA and come across a lot of different trailer hooks.
Ended up installing hammerlocks on my 2020 F-350 and this is the best solution I've come across so far.
They come in different sizes so you can select the max break strain you will need for your particular trailer.