3/4 " FS API Class SM coupling 1 Type: SM FS coupling New: Both-way Protection Globoidal Coupling Full size SM coupling with big chamfer 2 Material: Carbon steel AISI 5I40 3 Spray Material Ni60A Alloy Coating 4)Basic Hardness: HRC 16-23 5 Surface Hardness: HRC 55-62 6 Hole rate: 2% 7 Min. Hardness of the layer: 595HV0.2 8 Standard: API Spec 11B 9 Coupling diameter: 3/4 " 10)Weight: 0.60 KG/Pcs 11)Package: wooden cases 12)Payment Terms: T/T