LEITH EXPERIMENTAL DUPLEX TYPE C/PL.7 (AH AI BH BI)(SPEC.C6). A good to fine used 1855 die II 1d pl.7 block of four lettered AH AI BH BI L.C.14, several short perfs but cancelled several fine to very fine strikes of this scarce experimental cancellation DE 24 1855 code "+". BH shows fine constant variety DOT IN BASE OF T and DOT IN CENTRE OF NE SQUARE. Very fine and scarce multiple. (Ref 90150).