Package includes:100 pieces 4 mm earring pin studs,100 pieces butterfly earring backs,100 pieces bullet earring backs. | The earring posts pin is 12 mm in length, 4 mm pad in diameter, 0.7 mm pin thickness. | The butterfly earring backs is 5 mm in length, 3.5 mm in thickness. | The bullet earring backs is 4 mm in diameter, 4 mm in thickness. | Earrings posts with flat pad allows you to DIY your earring finding with some rhinestone and crystals flat back via hot liquid glue.