Hi, I was looking for one of those stops that mount on the back of the jaw...then I saw this

Set of 2 Machine Shop Vise Stops for CNC or Manual Mill Vise Low Profile | eBay

I'd have understood if the description says something doesn't quite make sense for me.

"This lets you machine the edge of any part right down to the jaw.

These are very useful in any kind of set up where you do not want to hit the stop itself with your tool."

can someone pls explain?