Any Information on these clip on ear rings?

by jen
(lawrence kansas usa)

Can anyone tell me if this is a recent piece or possibly how old it is. We got it in a box of very old jewelry with many clip on ear ring sets from my husband's Grandmother when she passed away.

There are several sets of ear rings that have the screw on backs as well. Just wanting to see what these are before we were going to allow our girls to play with them and wear them. Any help would be greatly appreciated.