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.


Country / Post Nigeria
Date of Issue 17 March 2011
Primary theme Geography & Meteorology (Waterfalls)
Subject Benue stamps - Gugur Waterfall on Katsina Ala River
Width 40.0 mm
Height 25.0 mm
Denomination 20 NGN
Number in set 4 (show set)
Layout/Format sheet of 50
Perforations 13 by 13
Stamp issuing authority Nigerian Postal Service
Printer Superflux