12¢ Gray Black, Block of Four, large margins at sides, just touching at top, tied by two of three strikes "Bristol R.I. Mar 10" cds on cover to Birmingham, England, red "38" credit handstamp and "America Paid Liverpool" (3.23) transit cds, reverse with "Boston Br. Pkt. Mar 11" exchange datestamp and "Birmingham Mar 24 1857" arrival cds; cover refolded at left with left vertical pair creased (and showing tiny abrasion) from where it was originally folded over the edge of the envelope, Fine and exceedingly rare, this is One of Only Five Or Six Recorded 1851 12¢ Issue Blocks Used on Cover. Scott No. 17; $5,500 off cover  Estimate $750 - 1,000. $0 (Image)