1854 DIE 1D PLATE 173 (RK) S.C.16 WATERMARK INVERTED (SG17Wi) ON COVER. 1854 envelope London to Rugby with fine example Die 1 plate 173 lettered RK in State I tied London '41' numeral. On reverse 'King William St' local receiver in blue and London datestamp 7/AP/1854 . Watermark inverted clearly seen when held up to the light. Very scarce usage. (Ref 49944).