National Pipe Straight Taps Marked Nps Are Suitable For Tapping Holes Our Couplings For Low Pressure Work To Assemble With Taper Threaded Pipe Or Fittings To Secure A Tight Jpint When A Sealer Is Used. They Are Suitable For Npsc And Npsm Work. Used To Make New Threads Or Re-Thread Damaged And/Or Jammed Threads