Old Ca. 1950s SWIM AT ~ WORLD’S LARGEST SWIMMING POOL ~ BALMORHEA STATE PARK ~ BALMORHEA TEXAS Stamped Metal License Plate Topper Sign. Marked ERICKSON-DES MOINES. Measures 6-1/4 X 5-3/4 inches. Check out photos. Be sure to take a look at my other old signs and advertising. Thanks!