This interchangeable dripper is designed with a self-cleansing, tortuous path, which slows the water as it is delivered at a uniformed rate from the reservoir of a Flood & Drip Shield. Since there is no pressure applied other than gravity, these drippers have been tagged The World?s Slowest Drippers. Deliver water and nutrients straight to the root zone of your plants with the subsurface design, which allows the drops to fall 3/4 inch below the surface and dispense out of the three slots at its bottom. Slowly deliver water and nutrients to your plants with the 1 mm or 2 mm pressure-compensating tortuous path. Reusable and made from BPA and lead-free plastic.