The Rain Bird A22441 is a RWSGRATEP RWS Purple Grate. Rain Bird’s Root Watering System enables vital water, oxygen, and nutrients to bypass compacted soil and directly reach tree and shrub root systems. The Root Watering System (RWS) Grate is a replacement in case of vandalism of the structure on any 36” or 18” model. The Purple grate option is available to indicate non-potable water sources. It is a genuine Rain Bird product.