Transition letter. Letter from Frederiksted during the transition period 1.4.1917 - 30.9.1917 to Copenhagen, Denmark. US 5 cent stamp tied by US datestamp 'FREDERIKSTED ---/21 1917 / SAINT CROIX'. 5 Cents equals 25 BIT UPU single letter rate. British re-sealing tape 'OPENED BY CENSOR. / 542'. ODENSE reception mark 20.8.1917.