It would take as much time to go to Google Translate as it will to enter the complete Finnish caption here, so here you are:  KESKI-SUOMEN ILMAILUMUSEO, PL 1, SF-41161 TIKKAKOSKI, MORANE-SAULNIER MS 50 C, Kaytetty Suomessa 1925-1932.  (We recognise this to be a museum exhibit.)  Mailed in 2013 with Moomin stamp and postmark and Priority label.  Some postmark transfer on the front.  Grade: 2