Hand-signed postcard entitled "Rucksackflug-Test" from his work "Groene Rugzak" from August 1984, a kind of flying backpack that he made, together with a "Silver Backpack" in his passage to the Furka pass in the Swiss alps.

The original photo was taken by German-Swiss photographer Vera Isler (1931-2015).

The postcard is in excellent condition.

With authenticity certificate issued by the Panamarenkoshop .