Chrysmela Catch Rose Gold most secure high tech earring lock earring back replacement for all types of earring posts auto adjustable auto locking hypoallergenic patented in 5 countries Chrysmela Catch, the most secure earring back with the lock-and-unlock precision technology Replaces all types of conventional earring backs Easy to use + comfortable to wear Hypoallergenic Fits earring posts, 0.6-1.1mm in diameter. (Most posts are 0.7-0.9mm.) Patented in 5 countries. Proven track record since 2008