These earrings are pretty small so be careful.  They measure 3/4" inside diameter, 1" outside diameter.  I wear 2 on my left ear, and they fit well enough, just smaller than I expected.  They open and close fairly easily and securely however if you sleep with them on like I do, you might tug one off if you roll around on your pillow a lot.  I had a pair that were ungodly hard to take off before and I prefer these ones even with that risk.  It locks well enough.