... 4.Surface: black, g screwed half coupling Black BS1387 Standard Carbon Steel Screwed Half Coupling screwed half couplingMaterialCarbon steel, Stainless steel, Alloy and Malleable ironStandardANSI B1 ... ,stainless steel ,alloy steel . Surface of screwed half coupling: cold galvanizing,hot galvanizing,and black Egdes: banded, beaded or plain Hydrostatic Test: Pressure ...