Material: The core blank rings are made of stainless steel with lasting color retention, polished inner surface and edge, exquisite craftsmanship and comfortable to wear. Gunmetal: Gunmetal grooved finger ring settingsabout 17/18/19/20/21/22mm inner diameter, 8mm thick, 24pcs,Note: The larger size may be slightly larger than usual, making it easier to manually DIYThank you for your understanding Easy to Use: You could inlay curb chain, brushed CZ, rhinestone, diamond, crushed opal, wood, opal domed and so on to DIY custom finger rings for couple or man. Fashion Design: Simple grooved band rings are very classic, with exquisite craftsmanship, bring you masculine and trendy. Application:It is perfect for ring jewelry making for both women and men. And it is suitable as a meaningful gift for your lovers, friends on valentine's day, christmas, thanksgiving, anniversary, wedding, engagement, etc.