1922-30 Bicolour 3rd wmk 1d red & green, perf 14, error wmk INVERTED. Superb fresh MNH, pristine never hinged original gum, right marginal with excellent centring. ACSC D106a cat $10,000++, SG D92w cat £6000++, both for M, should be at least double, MNH, so $20,000+ or £12,000+. Major rarity -only the 4th example ever offered for sale - one of the previous sold for $12,000+ in our auction 320. An important error stamp. Certificate can be obtained on request. (P) (Image1)