I know it's very expensive for a few bits of copper that you attach to the vise jaws, but I have to admit they are exceptional quality. They're thick and heavy, once you tap the "tails" to adjust them to the vise body they don't fall out, although they come loose easily if you have to use steel jaws, and they'll probably outlive me. Many years ago I made a makeshift pair of copper sponges out of a piece of old copper pipe and they worked fine, but they are genuine and in my opinion well worthβ¦