1973 15¢ Progress in Electronics - Audio & Visual Plate Block

United States #1501 8¢ Progress in Electronics - Transistors & Printed Circuits Plate Block

United States #1500 6¢ Progress in Electronics - Marconi Spark Coil & Gap Plate Block

United States #1502 15¢ Electronics Mint Single

United States #1475 8¢ Love Plate Block

United States #1509 10¢ Crossed Flags Plate Block

United States #1510 10¢ Jefferson Memorial Plate Block

United States #1488 8¢ Nicolaus Copernicus Plate Block

United States #1507 8¢ Christmas - Madonna Plate Block

United States #1504 8¢ Angus Cattle Plate Block