The Rain Bird purple spray cap fits on all 1800-series Rain Bird sprays. The purple cap is the only of it's kind and is intended to identify non-potable, or reclaimed, water systems. Identification of such systems is needed any time your water is sourced from previously used or processed water to ensure it is not consumed. Easy to install, the spray cap secures tightly to the top of any 1800-series Rain Bird spray in seconds, eliminating the need to extra tools and assembly. This spray cap can be installed on any existing 1800-series spray, reducing the cost of identifying non-potable water sources. The spray cap also features very clear Do Not Drink verbiage to further aid in preventing the consumption of reclaimed water.