So far they work great for me. I know some people have complained about the magnets falling out, I'll update my review if that ever happens to me. I will say one thing that worries me a little is that not all magnets are oriented the same so there is no guarantee that they will mix and match properly. This has the side effect that they line up nicely when there are two of you in the ring together. It generally works for me, but I can imagine that if they don't mix well with one another, someone's usefulness would be greatly reduced.
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