If you are looking for a lock/stopper for your chamilia, buy the authentic one, this is very difficult to insert in the bracelet, the rubber inside the stopper is so tight that I had to remove it to use the stopper. So at the end I have to use it like spacer... It is not functional at all because even though you can insert it, then when you want to change the charms you need to suffer again the painful task to insert the stopper.