First Day of Issue = June 15, 1933
Size: 36.00 mm x 30.00 mm
Quantity printed = 11,520
Perforated 10.00 x 11.50
Print method: Lithography

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

Watermark



Catalog numbers
Scott CB20a
Michel LV 227B

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