Extra-secure earring nuts with plastic flange and mechanical grip. These earring back findings are made in the USA of aluminum that is nickel-free and lead-free. The silvery color of these earring backs works well with silver, "white" metal, and rhodium earring findings. Durable mechanical grip: springy metal prongs inside grip post. Long-lasting grip, means less chance of lost earrings! Flange keeps large and/or heavy earrings flat to the ear.