30mm. Vintaj nickel-free brass fastenables. Identifiably named simply because you can fasten them to anything! Decorate metal, jewelry, paper goods, chip board, grunge board, wood, leather, acrylic, textiles, foil, canvas and more! Fasten, suspend, hammer, texture, layer, rivet, cluster, glue, alter, ink, paint and more to create all types of projects!