8x12mm. Vintaj nickel-free brass. Special Feature: Magnetic (MAG-LOK) providing a very strong hold and the ease of simply placing the two ends close together for a connection. This feature can be especially useful for individuals that do not have the mobility required to use common clasps. No glue is used in the assembly of these clasps. This item is a set of very strong clasps made with rare earth magnets. Clasps are essential for necklaces and bracelets. Give your jewelry secure (or creative) closure with this clasp. Simply connect one clasp on one end of your bracelet, necklace, etc, and the other clasp on the opposing end.