1919 2c carmine rose, unused with dried original gum, h.r., overall toning, well centered with intact perforations, v.f. A nice example of this Air Post rarity, signed Herbert Bloch. Only 200 copies of this overprint were prepared for the experimental flight from Barranquilla to Puerto Colombia. Approximately 160 were used on covers. Overprinting was done in horizontal strips of 10, which were severed by knife, causing most of the stamps to be defective, cat. $3500 (Cat No. C1) (Image)