Worldwide First Day Cover FDC Postal History World Widlife Fund, WWF , World Wide Fund for Nature These are the Official Proof Edition First Day of Issue Panels issued by the World Wildlife Fuind WWF in very limited quantities. The panels are full size items , suitable for framing as well, and will come in 2 heavy Black background Archival Quality Pages to protect them for years to come. Each issue also comes with the originally provided invaluable information pages that come with each issue or set. These First Day Cover Panels were prepared and sold by subscription service only by the World Wildlife Fund ( WWF ) and are the exclusive Limited Edition covers. All of the cachet artwork was drawn / painted by artists and signed, and were done only for this WWF set. Each issue highlights a specific animal, indigenous to that country, and produces typically four images on the four designs.