Anvil 8700162657, Malleable Iron Pipe Fitting, Locknut, 1-1/4" NPT Female, Galvanized Finish Locknut to connect two fittings or pipes for stability and reduced vibrations Female National Pipe Taper (NPT) threads for connecting to a male pipe or fitting Made from malleable iron for tensile strength National Pipe Taper (NPT) threads for creating tighter seals than straight threads Galvanized finish resists rust in water, air, and steam applications