Kilograms and liters
Kilogram is not an international legal unit, but a unit of mass in the international system of units. The international legal unit of mass is the kilogram. There used to be force and gravity.
And the non-legal units of pressure are also in kilograms. Such as how many kilograms of force is applied to the object, how many kilograms of pressure is in the pipeline, and so on.
Litter, usually referred to as liter for short, is a unit of capacity measurement. liter is expressed as L in the international system of units, and its secondary unit is milliliter.