12 Pack Magnetic Necklace Clasps and Closures. Necklace Jewelry Extender with Strong Magnet. Magnetic Necklace Clasp for Jewelry Necklace Bracelet Making. Gold and Silver Plating (Regular) is a Beading & Jewelry Making option for everyday use, business supply needs, resale shelves, or household stocking. Review product size, pack count, and shipping details before checkout.