1912 Envelope sent registered to St. Petersburg with 7k strip of three on reverse tied by oval “POTI-ODESSA STEAMSHIP 13 11 12” ds, with further strike on obverse along with “STEAMSHIP BATUM-ODESSA” registration label, arrival bs adjacent, opened and slightly re-folded for display, fine and rare registered use This line served the Caucasian and Crimean coasts. Its ships were inter-changed with those of the Batum-Odessa line and although possessing its own canceller, used the registration labels of its sister line