RAINBIRD SCREWDIFFU 203933 is specially designed by Rain Bird specifically for Maxi-Paw and Maxi-Bird Rotors. Breaks up the stream of water for more close-in watering. Shortens distance of the stream (throw) up to 25% of total throw. Screw clockwise into the stream to produce misting and shorten throw. Turn counterclockwise until totally out of stream for maximum distance (unadjusted throw).