Austrian Levant (1816) Constantinople Florence Stampless Disinfected Letter SFL

Stampless folded letter, with contents datelined Constantinople, to Firenze (Florence), Milan transit struck on front, disinfected at Rothenthurn (Austria), with hand-struck cachet "Netto di fuori e sporco di dentro" ("clean outside and unclean inside"), rastel spike holes, a nice example of this disinfection marking, scarce and fine.