... /4 In,NPT,Black Malleable Iron 1.Banded,Beaded,Plain 2.1/8-6" 3.Connection:NPT thread 4. ... Heavy/Standard/light weight Union, 3/4 In, NPT, Black Malleable Iron Specification ... :Union, 3/4 In,Connection NPT threads, Material ... Pressure:25kg/cm2Working Pressure:16kg/cm2Chemical PropertiesC:2.4~2.9 %Si:1.2~1.7 ...