The Save A Drop TM Green Nozzle can be easily added to your hose to monitor water usage for required needs. Over-watering plants and schrubs can diminish plant health. Measure with this meter and you can take all the guesswork out of delivering the right amount of water to all of your plantings. Now you know exactly how much water each plant gets and you can prevent root rot and other infestations before they take hold in your garden.P3IP0520. P0520. P3 P3 P0520 Save A Drop (TM) Water Nozzle.