Valyria 200pcs Stainless Steel Open Jump Rings Connectors Jewelry Findings (10mm x 1.2mm) Size:10mm(3/8") x 1.2mm;Hole size:7.6mm Size:9mm x 1.2mm;Hole Size:6.6mm Thickness:1.2mm Professional jewelry makers' must have Jump rings are used as a connector where a single ring is desired.