EZ-FLO Main Line Systems attach directly to your in-ground sprinkler and/or drip irrigation system. Every time you use your irrigation system, EZ-FLO releases small, precision doses of water soluble or liquid non-hazardous fertilizers into the water stream. One system will feed through both sprinkler and drip irrigation zones without the need to make any adjustments or nozzle changes to compensate for water flow or water pressure. Main Line Systems have been designed to connect directly to your irrigation system after an approved backflow prevention device. They are designed to withstand constant static water pressure present in your irrigation system. These units are constructed of heavy-walled, UV-Resistant PVC and have no moving parts making them very reliable, dependable and maintenance-free.