This jump ring kit includes 4600 pieces in 5 sizes: 4mm, 5mm, 6mm, 7mm, and 8mm, providing a large quantity and variety for jewelry making and repair projects. The closed jump rings are made of metal that is safe, durable, thick, sturdy, and perfectly aligned. The kit includes a jump ring opener tool for easily opening and closing rings to fix earring hooks, necklaces, and other supplies. All jump rings are neatly organized in a handy box with separate compartments for each size to prevent messes.