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.

BG004.15

Country / Post Bulgaria
Date of Issue 20 February 2015
Primary theme Science & Technology (Time measurement)
Subject Antique Clocks
Width 29.0 mm
Height 18.0 mm
Denomination 0.30 BGN
Number in set 3 (show set)
Layout/Format sheet of 100
Perforations 13 by 13
Stamp issuing authority Bulgaria Posts PLC
Printer Bulgarian Philately and Numismatics