Cook Islands 550-552 ad blocks

Cook Islands 550-552 ad blocks, MNH, $5.10. Michel 669-680. ZEAPEX-1980: Sir Rowland Hill overprinted: Postrider, Stagecoach, Automobile, Streamlined train, Cap-Horniers, sailing ship, River steamer, Liners "Deutchland", "United States", Balloon Neptune, Junkers, Graf Zeppelin, Concorde.