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.

US001.19

Country / Post United States of America
Date of Issue 10 January 2019
Primary theme Holy Days & Celebrations (Personal greetings)
Subject Hearts Blossom
Width 23.5 mm
Height 31.0 mm
Denomination Forever
Number in set 1
Layout/Format self adhesive sheet of 20
Perforations 11 by 11
Stamp issuing authority United States Postal Service
Printer