1/2 Inch, 17.5mm open diameter, 304 Stainless Steel. Specialized tongue-in-groove design which provide a full 360 degree seal. Premium quality NSF PW rated Pex cinch ring clamps recommended for all forms of flexible and inflexible thin walled hoses. 100-piece contractor size packaging. Recommended for outdoor or indoor use. Cambridge high quality products are trusted and preferred by both consumers and professionals. Have a question or need product support? Contact us through the buyer-seller messaging feature and our knowledgeable and a friendly customer support specialist will be happy to help.