You can use either adjustable arc nozzles or the preset Matched Precipitation Rate (MPR) nozzles. Both work just as well.
The fixed arc (45, 90, 180, 360 degree) nozzles simplify the design process by allowing sprinklers with various arcs and radii to be mixed on the same circuit. They are used when the angle or arc of the area needing to be covered by water, is regular shaped and one of these preset arc nozzles can be used.
The Adjustable nozzles for all standard and irregular-shaped turf and shrub areas or when you are not sure which preset nozzles you will need. Adjustable arc nozzles are great to order if you want to be sure you can cover all the areas of your yard, but you have not calculated which preset nozzles you need. You can't go wrong with adjustable arc nozzles since they adjust to fit any angle. Simple twist of center collar increases or decreases arc setting. No special tools required. Stainless steel adjustment screw to adjust flow and radius.
I suggest that you use the preset arc nozzles if the area is 90, 180, or 360 degrees so that you do not have to worry about something happing to cause you to have to adjust the arc every once in awhile over the years. The arc is set and will never need adjusted!
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