Plastic Threaded Plugs for NPT Pipe Fittings - P SERIES To Fit Thread Size: 3/4 NPT Series P Pipe Plugs are available in three styles: square head, round head and recessed socket. They are molded in high density polyethylene and are ideal for keeping moisture, dirt and other contaminants from NPT-threaded ports.Material: High-Density PolyethyleneColor: RedApplicable Specs: MIL-C-52078, MIL-C-5501/5, NAS 840