Issued in 1972, this Belgian stamp commemorates the Conference of European Postal and Telecommunications Administrations (CEPT) under the Europa theme of communication. The design features abstract radio waves or sound frequencies in dark blue and green against a pale blue background, symbolizing modern telecommunications and European unity through technology. The bold “EUROPA” header and value “3F50” mark this as a key issue from Belgium’s early 1970s Europa series — a must-have for collectors of European integration themes.