Lot 352, Canada 1930 five cent Air Mail die essay in black with “POST” at right

Lot 352, Canada 1930 five cent Air Mail die essay in black with "POST" at rightLot 352 Canada #C2DP 1930 5c Air Mail Die Essay in Black, mounted on thick card, with the word “POST” at right instead of “POSTAGE”. Very fine and quite rare, with pencil note on back reading “ex. John C. Cornelius”, accompanied by a 2018 Greene Foundation certificate. Estimate $3,500.