The concept of these seals is good, but the execution is very marginal. Specifically, they use very small magnets that absolutely cannot hold the pads in an iron vise. Once the vise is released, the pads will fall off. They would hold if larger rare earth magnets were used. An additional problem with them is that the jaw that fits over the top of the vise jaws is very narrow and tends to wobble, making the washers even easier to fall out with normal use. Not worth returning them, I'll try to drill holes and put more magnets in each one. However, due to the tiny magnets, I strongly advise against buying them.