Lead Free Brass Pipe Fitting, Locknut, Class 125, 1-1/2" NPT Female Locknut locks two threaded fittings into place for stability and reduced vibrations Female National Pipe Taper (NPT) threads for use with male threaded pipes and fittings Made from lead-free brass for higher corrosion resistance than steel Relative softness of metal enables tighter seals and greater ease in installation Meets standard ASTM B584-06 for lead-free quality assurance