The International Silver Co. 3175 hallmark designates a piece produced by the International Silver Company, likely part of a numbered line of hollowware. The four-digit number (3175) typically identifies the pattern or model of the item, such as a tray, bowl, or teapot. International Silver was known for producing both sterling and silverplated wares, though this format usually refers to silverplate. The company was a major American silverware manufacturer in the 20th century.