How did I not know these existed :-/ I feel like a bit of an idiot now for threading box steel and welding nuts on the backside of angle brackets.
The only thing I can complain about is that they came in plastic bags and not the small storage container pictured.
Very good quality and easy to use.
These are by far superior in quality and the bolts accurately fit.
I would highly suggest using a rivet tool similar to what I ordered: Astro 1427 Hand Rivet.
Check the size before buying.
Returned because they would not work for our purpose.