The B358 fits 9 gallons into 19.5 x 14 x 8 inches - shoebox proportions that make it one of the most placeable tanks Ronco molds. Eight inches of height slips under dinette seats and berth flats; the sub-20-inch length turns corners that longer tanks cannot. For van conversions and small boats, this is the capacity that covers a weekend of drinking and dishes without annexing a locker you needed for gear.
It is a true dual-role blank. Fresh fittings make it an FDA-compliant potable molding; waste fittings make the identical shell a compact gray or black holding tank - useful when the build's missing system is the drain side, not the supply side. Either way the ports are yours to place: print the drawing below, mark them with the fitting planner on this page, and Ronco spin-welds or thread-installs each fitting to your spec in Tustin, California, keeping a build-to-order habit unbroken since 1974.
At 13 lb empty it installs one-handed; at about 75 lb full it still demands a real strap and a flat landing - water does not care how cute the tank is. Neighboring small shapes fill the boat tank category and RV water tanks; waste-dedicated moldings are under RV holding tanks; and the full line is on the Ronco Plastics hub. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B358 dimensional drawing - print it to plan your install and mark exactly where you want fittings located; Ronco installs spin-weld or threaded fittings to your marked spec.
