Is this item drinking water safe? Yes.  Water flowing through your ELEY reels, hoses, and watering tools stays pure because we use only 100% drinking water-safe internal component materials. From the lead-free brass and rubber seals down to the assembly lube—it’s all safe.  High-grade materials Designed and made for years of use, the pro watering nozzle is constructed from durable brass and stainless steel, and it's 100% drinking water safe. The O-ring gasket and threaded nozzle provide a water-tight seal to guarantee zero leaks for 10 years! Why are there 4 screens?  This innovative watering nozzle comes with four interchangeable stainless-steel screens, allowing you to select the best spray pattern for your watering needs. The screens are labeled in minimum flow required, 1, 2, 3, and 4 gallons per minute (GPM). If your water supply has low flow, meaning you have low water pressure or volume, then you may need the 1 GPM Minimum screen to produce a spray pattern that doesn’t dribble. On the other hand, if your system has plenty of flow, then the range of screens allows you to choose a spray pattern that reaches a further distance (1 GPM Minimum) or delivers more volume (4 GPM Minimum). The maximum flow for each screen is 7, 12, 18, and 25 GPM, respectively. However, your actual flow may be affected by the volume of your system at the faucet and the length and size of the garden hose used. The included, user-friendly screen change tool makes it easy to switch out the screens until you find the perfect match to fit your watering needs.