Rockin Beads Brand, 400 Strong Jump Rings, Antiqued Copper Red Bronze Plated Steel, 5.5mm Round, 20 Gauge. Pre Opened 4mm Inside Jewelry Connectors Chain Links Sold Per Pkg of 400 Antiqued Copper also called Red Bronze Plated Steel for extra strength .75mm thick 5.5mm outside 4mm inside Pre Opend 400 per package