Will according to Wikipedia: the triangular frank depicts Israel Defense Forces logo (sword wrapped by an olive branch) and denotes the sender's military unit postal identification. It doesn't have an Israeli Military censor sticker at the side, so more than likely is not a censor cover.
This type of frank came into force in the 1960's and your cover is addressed to Tel Aviv.
The Wikipedia link:
http://en.wikipedia.org/wiki/Israel...itary_Censor