Material:Nickel Plated Metal Base Feature:These are known as Bead Cages,Spiral Beads and Lantern Spring Beads.They can be used on their own,or used them with beads inside(thread through the cage and the bead) to add a special touch to your Jewellery. The cage can stretch to almost double its size to hold any item as required Size:3cm long X 2.5cm wide,Space:3mm,Hole 6mm