Rainbird 15CST 15' Center Strip Pattern Nozzle Matched precipitation rates across sets and across patterns in 5 series, 8 series, 10 series, 12 series, and 15 series 20 series nozzles meet small-area shrub or turf requirements. 23 series nozzles have a lower water flow which allows more spray heads per zone. 1815 series white filter (.035" x 035") screens (shipped with nozzles) maintain precise radius adjustment and prevent clogging. Stainless steel adjustment screw to adjust flow and radius.