These are pretty small. Good size for a child, or for adults who just want something small and subtle. I haven't noticed any issues with the earring backs, but just to make sure, I tested the earrings with some generic backs that I got from a craft store, and those feel more secure.

The only bad thing is that I got these as a gift for a friend, and each individual pair of earrings comes inside its own small plastic bag, and all of these small plastic baggies are inside another, slightly larger plastic bag. That's sort of an awkward way to present a gift, and a bit of a waste of plastic. There aren't any issues with the earrings themselves, however.