Material:925 sterling silver. It still keep bright and shining after used for a long time,high quality. Size:outer size:18mm,inner size:11.7mm,thickness 3.1mm, hole 3.1mm,package:1 piece silver original. Easy and Safe:Open and close easily; It's very reliable; With this clasp, one thing is for certain, there is absolutely no chance that the chain will be able to exit the ring on its own accord. This means that you can enjoy wearing your jewelry without any fear of it getting lost. Usage:Incorporated into the ring is a small spring which is compressed when a tiny lever is pulled back revealing a gap in the ring. A chain or loop can then be inserted into the gap. Releasing the lever will cause the gap to be completely closed up. Wide Application:The spring clasps can be used to create your unique jewelry crafts, suitable for making adjustable necklace, bracelet, anklet and more, you can also use. 925 Sterling Silver Spring Ring Clasps 18mm Round Close Ring Clasp Connector Finding for DIY Bracelet NecklaceNecklace Jewelry Making Craft(Silver Original),material:925 sterling silver,color:silver original,size:outer size:18mm,inner size:11.7mm,thickness 3.1mm, hole 3.1mm,package:1 piece.