JWB Card of SS Rijndam
These postcards were issued by the Jewish Welfare Board (JWB) for returning US troops. JWB cards were given out to the people onboard the troopship, and did not require a stamp, if mailed onboard or at the dock before disembarkation.
The Rijndam was leased from The Netherlands for the duration of the war.
Information on troopships of WW I at: my troopship pages.
Found image enhanced with GIMP.