1.5" with covered tin back stamped by name of St. Louis maker W.H. Haskell. One from a series of real photo buttons depicting various attractions at the fair. Button should be viewed with a glass to see the incredible detail. Without a glass the tall inclined ramp is shown with cars that plunge down into water. Numerous people pose, looking towards the photographer. With a glass even several names on the ends of the boats can be read and these include Brooklyn, Winslow, Indiana. At the center framed in entrance area to the ride is a large sign board reading "Lemp's Beer." Button surface is just a hair concave with three air spots that catch reflected light. The only stain is an 1/8" spot on extreme upper edge that blends well. Rare. Also see from this Expo Indian Congress button #658. Scarce.