That's Flexible Bioplast PVC Plastic Ear Pin Bone Stud Nickel Free Earrings Piercing Retainers Earring Stud Mix Color

Unfortunately the posts twisted out of shape when trying to put on a variety of backings- none of which would go over the posts. Couldn't wear. What a shame. Pretty colors and really tiny.

GREAT

Without a back I've lost 4 of these in under a week, and will have to buy different ones don't waste your money