 Many North American dishwashers tend to use exposed elements in the base of the dishwasher.Some North American machines, primarily those designed by General Electric, use a wash tube, often called a wash-tower, to direct water from the bottom of the dishwasher to the top dish rack.Some dishwashers, including many models from Whirlpool and KitchenAid, use a tube attached to the top rack that connects to a water source at the back of the dishwasher and directs water to a second wash arm beneath the upper rack, this allows full use of the bottom rack.