Mine did not come with backs to fasten them on but at first I wasn't worried since I can steal a pair of those white foam things from another pair.  But then I put them on and they're made weird.  The dangly thing hangs off the loop so far back on the loop that the loop either sticks out in front further than the dangly thing, or if you push it in deeper, then you see the big long curved thing that sticks out the back - WAY out.  Maybe they could be bent or you could use wire cutters to trim them, not sure.  If I'd paid more for them I would give them only 1 star.  Also wonder if I'm doing something wrong.  Earrings should not need instructions but I'm curious how the manufacturer intends these to look in my ears.  (I'll never wear these)