1/4 in Female national pipe thread inlet. 3.5 mm orifice multi-regulator nozzle. Used when high and low pressures are needed. This nozzle easily switches between a solid or flat spray pattern without having to change nozzles. The low pressure mode is great for the introduction of downstream soaps. The spray pattern adjusts from a solid 0 deg to a flat 80 deg spray pattern with a twist of the nozzle head.