1) Materials: AISI 5140, ASTM 1045 2) Standard: API Spec 11B 3) Class: T& SM , Sub Coupling 4) Main specification: 5/8", 3/4", 7/8", 1", 1-1/8" 1) Materials: AISI 5140, ASTM 1045 2) Standard: API Spec 11B 3) Class: T& SM , Sub Coupling 4) Main specification: 5/8", 3/4", 7/8", 1", 1-1/8"