Iron Jump Rings, Close but Unsoldered, Golden Color. Size: about 4mm in diameter, 0.7mm thick, 12000pcs/500g. Iron Jumprings are a basic component in jewelry making and design. It is popularly used as a connector in jewelry construction. It can be used for attaching charms to necklaces or bracelets. Get Best Seller, 1000g Golden Color Iron Jump Rings For $5.77 @PandaHall.