Quantity and Size: Stud Earring about 12x4mm, Pack of 300pcs,300 pieces stainless steel butterfly earring backs and 300 pieces plastic earring backings.How to use it:Just use liquid glue to stick gems or small pattern accessories on the earrings post flat pad,making your homemade stud earrings a unique personality.cks are made of rubber, so you don't have to worry about ear allergies.Material: Stud Earrings are made of 304 stainless steel, sturdy,not easy to break, deform or bend,earrings are showing metallic luster, low sensitivity and no harm to the ear.Earring Supplies:The DIY earring supplies contains earring posts and backs besides the charms for earring making, which can be applied to make all kinds of stud earrings, as well as to repair your favorite earrings or other jewelryWide Application:Earrings backs fit to most of the earrings posts, are suitable for daily use, parties and activities,can also be used as a perfect match for weddings, decorations, and artworks. they are prefect gifts for your friends and family members.