Material: 316L surgical stainless steel. Hypoallergenic?? allergy-free</br>6 pairs/set?? size varies from 3mm-8mm</br>All earrings exceed all F.D.A / E.C requirements</br>Comes with Butterfly Earrings backs?? are grooved friction post for secure fastening</br>Packed with velvet box?? free 2-days fast shipment for prime members</br></br>Product Description</br></br><b> Product Information: </b> <br> <b> Back Type: </b> Friction<br> <b> Metal Color: </b> Grey <br> <b> Metal Type: </b> 316L Surgical Stainless Steel<br> <b> Stud Size: </b> 4mm?? 5mm?? 6mm?? 7mm?? 8mm<br></br><br/>http://www.amazon.com/gp/product/B01E3O9AK4