AGS cap screws are made of low-carbon steel and are common in construction or repair projects. Working temp (pressure): -65 degrees F to 250 degrees F. Applications include metal-to-metal fastening. AGS brass and steel fittings are comprised of Tube Nuts, Unions (Couplers), Adapters, Elbows, Tees, Bushings, Connectors, Grease, etc... AGS fittings are held to the strictest standards to perform flawlessly in their intended applications. Fittings are offered in a variety of packaging options, including retail clam-shells, bulk boxed, and plastic tray assortments.