Watch List notes:

The Pavilion Collection, Commemorative Medals, The Counterseal of a Seal of Office of King George IV, 1820, a bronzed electrotype of a seal-matrix, for an undesignated seal of office, Thomas Wyon Sr. (1767–1830), chief engraver of the seals; the King in armour rides to the right holding a baton before him, in ex. the Prince of Wales's plumes, GEORGIUS QUARTUS DEI GRATIA BRITANNIARUM, 96.74mm., the piece lead-filled, the impression taken from a mint state seal-matrix, as made and extremely rare
Being a seal matrix the image and letting are in intaglio and, of course, reversed.
(80-120 GBP)