Anvil 8700130068, Cast Iron Pipe Fitting, Hex Bushing, 3" NPT Male x 1-1/2" NPT Female, Plain Finish Hex bushing for connecting two pipes of different sizes Male National Pipe Taper (NPT) threads on the outside and female NPT threads on the inside for creating tighter seals than straight threads Made from cast iron for compressive strength and resistance to wear Hexagonal head for increased leverage and use with a wrench during installation and disassembly Plain finish for corrosion resistance in oil and gas applications