These are great! I wanted extra security for my diamond earrings. This is the solution to the problem of earring backs that may slip off. They are a little spendy, but if you wear fine jewelry and worry about losing your investment you should buy at least one set to wear with your earrings. I am active so I need the extra security. They fit well and my earrings are ultra secure. Too bad fine jewelers don't include these with their diamond earrings. I would have paid extra for them if they had been offered.