Enlarged, four-piece model showing the effects of COPD on the bronchus and alveoli. The bronchus cross-section shows a healthy bronchus and the mucus hypersection resulting from COPD. A healthy aveoli is contrasted with an emphysema aveoli with cross-section showing wall destruction and decreased, larger alveolar ducts. Model measures 1.375 x 1.75 x 1, and the Alveoli measures 1.75 x 1.75 x 2