The World Association for the Development of Philately (WADP) and the Universal Postal Union (UPU) jointly conceived and developed the WADP Numbering System - WNS, which was launched on 1 January 2002.

BE004.11

Country / Post Belgium
Date of Issue 17 January 2011
Primary theme Science & Technology (Physics & chemistry)
Subject Chemistry - Deciphering the material
Width 27.66 mm
Height 40.2 mm
Denomination 0.61 €
Number in set 1
Layout/Format sheet of 10
Perforations 11.5 by 11.5
Stamp issuing authority La Poste De Post Belgique
Printer La Poste - Imprimerie du Timbre à Mechelen