I bought a set of 3mm studs to use for ear cartilage piercings, and they work perfectly for that use. I can wear sterling silver in my regular lobe piercings, but my cartilage piercings were irritated by sterling and these have been fine. I like the screw backs because they look and feel better, too. They have shorter posts than usual, so they might be more difficult for some people to put in / take out.