Four-piece model of progressive stages of GERD. Conditions include: normal, sliding hiatal hernia and acid reflux, chronic acid reflux/Barrett's esophagus, and Barrett's esophagus/adeno carcinoma. Made of durable, high-quality materials. Each of the four models measures 4-1/2 in. x 3 in. x 7/8 in. Card size: 6-1/2 in. x 5-1/4 in.