The dual adult test lung features our largest tidal volume capacity (4L) and comes equipped with accessories capable of simulating both upper and lower airway resistance. The Dual Adult Training and Test Lung: Is capable of spontaneous creath simulation. When coupled with our Breath Simulation Module, the dual adult lung becomes a spontaneously breathing unit, capable of simulating patient demand and other related scenarios. Allows for side-by-side comparison of pulmonary pathologies. The dual action of the model 1600 and 5600i test lungs allows the user to simulate two different pulmonary environments at the same time, making comparison (visual and otherwise) easy.