Beautiful Bead Column Spiral Swivel Screw Clasps Chain Connector for Jewerly Making Silver 1 bag of 50 pcs barrel swivel screw clasps, jewelry making supplies. Built-in safety screw Lock which are well made and highly durable and easy to screw together. Each screw clasps measures approximately 4x15mm. They're the perfect size and each with an open ring on each end. Fastens the ends of either a necklace or a bracelet together by screwing two pieces together that form a shape of a barrel. Perfect for your homemade jewelry or repairing your existing jewelry or making necklaces, anklets, charm bracelets or any craft, fashion projects with ease.