First of all, you must have a pressure reducer in your RV's fresh water line. The fixtures in all RV's are rated at a maximum pressure of 50 to 60 psi. Campground water pressure can be over 100psi. The surest way to burst a fitting or fixture is to let this high pressure water go into your city water inlet. This device is a cheap way to avoid that problem.There are pressure regulators that sell for a lot less than this one. They are fixed pressure reducers, mostly 45psi. They can be problematic. Check your RV's specs. My fixtures are rated at 60psi, so with this unit I can accurately set the city water pressure to what I like. I normally have it at 50 to 55 psi. This pressure vastly improves showers and dish washing. The pressure meter gives you an instant view of the water pressure...so if there is a problem, you can easily rule out the city water first.Some tips on using this device:1. This should be the first thing connecting to the campsite's city water connector. I follow this with a water filter and then my supply hose. By putting this regulator first, you protect your filter and hose as well.2. If you want to adjust pressure, do it ONLY with all water turned off inside the RV. Make sure that no water is running or filling anywhere. Once done, gradually move the adjusting screw a bit. Wait 10 to 20 seconds and look at the pressure. Once set, you can begin using water. When water is running, don't expect the reading to always be at the set pressure.3. Replace this unit after a year or two. All pressure reducers wear out. For safety, I replace mine every year. $50 isn't a bad investment in protecting my water system.4. Use a water filter! There are lots of inline filters available. Most screen out particles bigger than 30 microns or so. this is enough to protect your fixtures. These inline filters do not purify the water. They just remove sediment in the water line. We never drink campground water. We do carry a good quality purifying filter and bottled water.5. Avoid banging up the regulator. This unit is not indestructible. We keep it in a plastic container in our &#34;garage&#34; when we travel.SummaryYou will be surprised how much better a shower in the RV can be when you can control the city water pressure. This unit does the job at a good price.