NIBCO Coupling with dimpled tube stops are made from the highest quality raw material. All Nibco fittings are made from pure copper meeting current Lead-free requirement per ASTM specification B75 alloy C12200. Material and workmanship for all Wrot Copper pressure fittings is in accordance with ASME/ANSI B16.22 Dimensional, material and workmanship meets the requirement of MSS SP-104. Big size 5"-12" fitting meets the requirement of MSS SP-109. Third party certified to NSF/ANSI 61 standard. NIBCO Copper fittings are made from USA factories with stringent quality control ISO 9001 system, we are so confident to present NIBCO products for all your relevant application.