Female national pipe thread (F-NPT) x 4.5mm orifice stainless steel sewer nozzle. Slides easily into drain pipes and sewer lines. Great for flushing debris or clearing frozen pipes while attached to a sewer hose. Forward and backward ports in the nozzle blasts into the clogged pipe, breaking up the debris while pulling the hose through the pipe. Made of corrosion resistant stainless steel and designed to be small enough to clean in all the tight spaces. 4,200 PSI.