The loop where the end of the strap goes under, is called a keeper. This is a part of the (SKX007) strap that will break sooner or later, when it is made of rubber. Another disadvantage of that original rubber keeper is that it is rather thick, so it leaves a mark in your wrist (and it is not comfortable).
This stainless steel keeper looks cool, does not break and is less than half the thickness of the rubber one, I cannot think of disadvantages.
It fits on a strap of 20mm wide, and will take 2 x 6mm thick rubber. So it can be used on the SKX007 strap. Unfortunately, the new silicon straps of the new turtles are just a little too thick (but those already have a steel keeper).