This is a rare and high quality manufacture “Klasse D” International Gliding Commission (IGC) - Internationale Segelflugkommission (ISK) - Federation Aeronautique Internationale (FAI) gliding proficiency button-hole badge; in silver and fine blue and white enamels; reverse numbered “9135” and marked “935” (for silver content); measuring 21.84 mm in diameter; weighing 6.6 grams; very faint contact marks but otherwise near mint condition.
Footnote: The International Gliding Commission awarded a series of proficiency badges to glider pilots on their successful completion of the appropriate tests and gliding trials. The “D” class certificate was awarded for the completion of a 50km solo flight, lasting 5 hours, and having gained 1,000 meters in height.

