Avoid water
Works very well. I like these a lot better than the standard earring backs. However, the problem is that you can't get these backs wet in the shower or swimming or whatever, they will rust and turn a dark brownish blackish color. This only takes one star off for me, as it's not too hard to take off earrings before a shower, but I sometimes forget and end up with rusty earring backs.
Rating: 4 stars