Duratrac Yellow Coated Stainless Steel 3/4" MIP x 3/4" FIP Full Flow (1" OD) Gas Flex Connector (18") Yellow coated polymer exterior & double corrugated for extra protection and flexibility Comes with MIP and FIP flare fittings with 3/4" full flow inner diameter Compatible with Brasscraft CSSB21 for high rating BTU CSA certified and ideal for indoor and outdoor use Application includes residential/commercial tank and tankless water heaters, boilers, fryers, stoves