This is a Palestine Registered Censored Cover.  It was sent from Ramallah to Boston on 12/31/1918.

It was sent with a pair of Palestine SG 1, the 1 Piastre Indigo stamps as postage.  These were tied with an OETAEEF JERUSALEM CDS.  That stands for Occupied Enemy Territory Administration Egyptian Expeditionary Force.  It also has a CORNERLESS BLACK PALESTINE CENSORSHIP No 1.  It also has a Registered Label #78 and a REGISTERED LABEL in MAUVE. 

Additionally, there is an FPO with and inverted A on the back dated 1/1/1919, an FPO CM 1 London, and Boston Receiver marks dated 2/8/1919.

This item is over $100 USD so I will ship it using Priority Mail in the US, and Registered Mail overseas.  This is to ensure that it reaches you in a safe and timely manner, and includes tracking!