First Day of Issue = June 15, 1933
Size: 36.00 mm x 30.00 mm
Quantity printed = 10,720
Perforated 10.00 x 11.50

Stamp shows a biplane taking off. The surtax was for wounded Latvian aviators.

Watermark



Catalog numbers
Scott CB18
Michel LV 225A

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