THERLO, also known as D-H Alloy No. 373, is an iron-nickel-cobalt alloy ideally suited for sealing to glass. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: Fe-11. Producer or source: Driver-Harris Company. Originally published July 1956, revised August 1961.