These silicone earplugs are ANSI certified, and include a weighted nylon string to help them stay put. Each set includes a 3 1/2" x 3/4" plastic protective case with a short beaded chain to connect to a keyring. CE EN352-2, ANSI, AS/NZS 1270 Certified. NRR:23dB;SNR:28dB. Vinyl Insert imprinting is also available. Swag Book does not include product.