The Phyn Plus works with 0.75"" to 1.25"" water lines. Phyn Plus has 1"" NPSM male threaded ends. At the larger diameters there is a negligible change in flow or pressure. We have done extensive testing on this and it will not be anything impactful. At extreme flow rates like 25 gallons per minute it would only incur a PSI drop of less than 7 PSI.
Please refer to the chart below from Phyn Engineering.