These are heavy duty stainless steel jump rings in sizes 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or 12mm.These are available only in the Closed style (unsoldered but in the closed position).
Heavy Duty Jump Ring Kit, Assorted Sizes, Stainless Steel, 16
Heavy Duty Stainless Steel Jump Rings, 1.2mm thick - Jewelry Tool Box
50pcs Stainless Steel 1/1.2mm thick 6 8 10 12 14mm Twist Open Jump
Craft Sha Flint Leathercraft Creasing Tool 1.5mm Adjustable
Findings - Stuller
Door frame steel 1.2mm thick right hand opening W813mm x
Model Engineering and engineering tools online from RDG Tools Ltd
Craft Sha Flint Leathercraft Creasing Tool 1.5mm Adjustable
Jump Ring, Split Rings & Connector Links