For a weekend camper, the RVB545 is close to the ideal ratio: 53 gallons of fresh water in a molding that weighs just 42 pounds. That is enough supply to keep a small rig or camper van independent from Friday to Sunday - drinking, cooking, dishes, quick rinses - in a tank light enough that fitting it is an afternoon, not a project. Not every build needs the biggest tank in the book; most need exactly this.
It is a Ronco B-series light-duty molding in translucent natural polyethylene, FDA compliant for potable water, produced in Tustin, California on tooling the company has run since 1974. The translucent wall gives a direct visual on remaining water - lean into the storage bay with a light and you know precisely where the weekend stands.
The fitting layout is decided by you, executed by the plant: spin-welded or threaded ports at whatever positions your plumbing calls for. Print the technical drawing below, mark fill, vent, and supply, and run the fitting planner on this page before ordering. Even at this size, plan for the full-tank load - water is 8.34 pounds per gallon, so give the tank a solid, supported floor.
The RV water tank category has the smaller stock sizes if 53 gallons is still more than you need, and the Ronco Plastics hub shows the entire range if it is less. OneSource Plastics is an authorized Ronco Plastics dealer.