This stamp from the Crosby Collection was featured on Stamp Auction Network, in our advertisements and mailings, and on the cover of our print catalogue.
Lot 570 Prince Edward Island #2b 1861 3d blue Queen Victoria, Perforated 9, with Double Impression of the entire design. Unused (no gum), exceptionally well centered with bright fresh colour and intact perforations, with a small thin (not mentioned in the accompanying 2017 Greene Foundation certificate). 
Based on our research, we are aware of only four other single instances of this major error, at least one of which was part of the Jephcott horizontal strip of three. The Crosby item offered here is by far the best centered example, and has full intact perforations; the small thin is irrelevant as all of the single stamps mentioned above have thins (in addition to cracked gum, ragged perfs, poor centering, etc.). The most attractive example recorded. From the Louis Sidney Crosby Collection of Prince Edward Island. Unitrade CV$6,000, sold for $3600 plus buyer’s premium.
