Sterling Silver 4 mm Magnetic Clasp Converter for Light Necklaces USA, Square Edge Sterling Silver w/ the most powerful rare earth magnets on the market today perfect for people with long nails, arthritic, limited use of fingers nickel free, allergy free and wont turn your skin green wont make your jewelry look Cheap 4 and 5mm magnetic clasps are NOT strong enough for bracelets, we only recomment 9mm size for that porpose, and if the bracelet isnt heavy