First Day of Issue = June 15, 1933
Size: 36.00 mm x 30.00 mm
Quantity printed = 10,420
Perforated 10.00 x 11.50

Stamp shows a map and planes. The surtax was for wounded Latvian aviators.

Watermark



Catalog numbers
Scott CB20
Michel LV 227A

For more information check out the links below
Latvian airmail semipostal stamps
Latvian aviation