It's dismaying to come home at night and find one of your most favorite irreplaceable earrings missing because it worked its way out of your ear at some point during the day. I don't know how many single "fish hook" back earrings I have, but it took losing quite a lot of them to wake me up to doing something about it.  I decided, unless I wanted to adopt some new avant-garde pirate look and start wearing singles, I needed to find a way to keep both earrings in my ears all day. I tried using the backing from post earrings to lock them in place, but these didn't always fit properly or they made the earring hang oddly.  When I happened upon these clear rubber backs, I was ecstatic and ordered them immediately.  They're so cheap and I got a little packet in the mail a few days later and haven't lost an earring since.  WELL worth the price and shipping.