Pandahall 1Box/590pcs 6 Colors 3mm Iron Half Round Open Crimp Beads Covers Knot Covers Beads End Tips for Jewelry Makings Antique Bronze & Red Copper & Black & Silver & Golden & Platinum Lead Free 6 Colors: Antique Bronze & Red Copper & Black & Silver & Golden & Platinum Metal Finish: cadmium free & nickel free & lead free. Size: about 3mm wide, hole: 1.5~1.8mm; about 590pcs/box. Crimp covers are open on one side allowing them to slip over the crimp tube.They are designed to fit over the crimped bead or tube. They look like a bead, so it gives the design a more finished look. They are used with beading wire to secure the start and finish of the strand by crimping the crimp beads. Using the right size crimp bead or tube is also very important. If the crimp is too large for the jewelry wire, it won't be able to grip the wire properly and it could slip, causing the jewelry piece to fail. If the crimp is too small, particularly with crimp tubes, the jewelry wire won have room to separate for the crimp action and you won't get a good fold.