Whooshh tubes work on the principle of pressure differentials. Once an object is inside a whooshh tube, the slippery flexible whooshh tube makes a seal around the object. A pressure differential is created across the object by either increasing the pressure behind the object (push system), or lowering the pressure in front of the object (vacuum system). This pressure differential acts on the surface of the object to create a motive force and since whooshh tubes have very low coefficients of friction the net force propels the object down the length of the tube. Whooshh tubes can be used as either push (positive pressure) or pull (vacuum) configurations depending on requirements.