Tarnish Resistant 304 Stainless Steel Magnetic Clasps with Glue-in Ends, Column, Stainless Steel ColorSize: about 17mm long, 7mm in diameter, hole: 4mm.Excellent for bracelets or necklaces making. They have a great strong magnet which can help to connect your favourite necklaces or bracelets. This is a very easy design and must bring your jewelry more personal feeling. These are great for people who struggle with normal clasps!