This military-style canteen was manufactured by the Pressed Aluminum Company (PALCO) of Worcester, Massachusetts, during World War I era. The patent date of May 4, 1915 places it at the beginning of America's involvement in the Great War, when aluminum canteens were becoming standard military issue due to their lightweight and durable properties. These canteens were used by American soldiers and civilians alike during the early 20th century. PALCO canteens are highly sought after by military memorabilia collectors, camping equipment enthusiasts, and historians interested in World War I artifacts. These items appeal to collectors of early aluminum manufacturing and American industrial history, representing an important transition from traditional materials to modern lightweight metals in military equipment. The distinctive pressed aluminum construction and clear patent markings make these canteens valuable pieces of early 20th-century Americana. Shows wear.