I do not know what they are rated for but I do know that they will break if your saw is snagged. This happened to me when I was cutting some Tulip tree chunks.
Here's what I do for the Zubat. The short strap with clip lives on the harness, and when I want the saw I just clip it on. The little green biner hooks to the waistband inside the "D" and is totally hidden away.