We have a toilet unit that is sensitive to pressure so to us, having the right water pressure is very important. You can get water pressure regulators that simply screw onto you water hose, but with most of them, you cannot “SEE” what the pressure actually is.
That is why we prefer this model. It has a gauge that will tell you exactly where you are at and, of course, it will make sure the pressure is constant at around 45 PSI. Our coach will be fine with pressures that are much higher (our lines are PEX, which is rated at 160 PSI at 74F), but a low pressure can be problematic too so it is really nice to SEE what the pressure is. For a few bucks more than the units without a gauge, this is very much worth it.
Valterra A01-1124VP Lead-Free Water Regulator and Gauge Combo