This issue was produced by The American Bank Note Company in New York.  Authorized by the Danish Legation in New York as Denmark was still occupied by the Germans.  

VERY FINE + Never hinged.  The "Specimen" overprint indentation shows on the gum side (not a hinge mark !!).  

Only 300 sets were produced and 100 of these were in damaged condition and most likely destroyed.  A full set of sheets (100 sets) are still thought to be intact - Danish Postal Museum?  Thus only 100 sets were available for sale.  Means the block above is 4% of the available world supply.

IN the 1990's, there were various auctions of ABNC archival material and these and other die proofs and essays were found.

Various retailers / Scandy stamp dealers are selling single specimen stamps without lathework at $150 to $200 each.   Thus $600+ for 4 stamps alone and no added premium for lathework.

See my other Ebay listings for similar Greenland American Issue Specimens.  I combine shipping for multiple purchases.