As the name suggests, sub base tanks are designed to fit above the ground but below the base of the generator set. Sub base / diesel fuel tanks are rectangular in cross section and constructed using heavy gauge welded steel. Installation is simple. In most case you remove the rubber fuel lines from your existing tank and fit them on to the new tank with hose clamps.
The fuel tanks have air vents and are not pressurized. Most generators have built-in fuel tanks but, when more fuel storage is required, these diesel tanks are one option to choose from.