In conjunction with the issue WWF stamp series, Sao La, Vietnam Post issued the official first day cover which have a specific post marked. This local WWF cover has sealed with 4 postage WWF stamp, depicted Sao La.
The Saola (Pseudoryx nghetinhensis), Vu Quang ox inhabits the Annamite Range's moist forests of Vietnam and the Eastern Indochina dry and monsoon forests. They have been spotted in steep river valleys at about 300 to 1800 m above sea level. These regions are distant from human settlements, covered primarily in evergreen or mixed evergreen and deciduous woodlands. The species seems to prefer edge zones of the forests.
