This Digestive system anatomy model shows 4 progressive stages of GERD. Conditions include; Normal; Hiatial hernia and Acid Reflux; Chronic Acid reflux/Barretts's Disease; Chronic Acid Reflux/Barretts's Esophagus/Adeno Carcinoma. Anatomical model size is 4 1/2" x 3" x 7/8".