With our own unique technique, grooved fittings is made of processing stainless and steel pipes , not a casting. They are designed to prevent leakage from pin-hole. This product is manufacturing based on EM0072.00 in Korean agency for technology and standards. Our product is applicable to various piping systems with grooved coupling. We have also UL, FM approvals and internationally recognized registers of shipping (ABS, LlOYD, KR, etc).