This item is a collectible piece of commercial dinnerware produced by Buffalo China, specifically from their "Cafe Ware" line. 

• Manufacturer: Buffalo China, a notable American company based in Buffalo, New York, known for durable restaurant ware. 

• Line: "Cafe Ware", often characterized by a tan or beige body color. 

• Date Code: The mark "E 11" likely indicates a production date code related to the month and year of manufacture. 

• Status: The company is now defunct, having been sold and eventually renamed