RGK-9-22C-5/8 is a type of coupling, specifically a full-flow, flanged straight spigot, rigid coupling. It is part of ITT's DuroLink™ Expanded Range of Rigid Couplings. It is made of tapped-hole case-hardened steel and is designed for use with copper, copper alloys, and small bore size plastic piping systems. It is great for connecting two pipes, or for connecting a pipe to a tank or valve. It is easy to install, has a compact design, and can handle temperatures between -20°F to +200°F.