Etzioni Brigade "Defender of Jerusalem" variant badge, circa. 1948; weight: 3.4g. A solid-back badge with safety-pin reverse (typical of Israeli badges of that time).
Though not documented in standard militaria literature, this appears to be a version of the "Magen Yerushalyim" badge (see item 0132028) issued to members of the 6th Etzioni Brigade, which served in the Jerusalem area during the War of Independence: the brigade's emblem is the crenelated battlements of the wall of Jerusalem with a shield and the sword emblem of the Hagana superimposed on it (but without the word "Jerusalem" below the sword, as on the Defender of Jerusalem badge).
סיכת מגן ירושלים לחיילי חטיבת עציוני תש"ח מלחמת השחרור עצמאות, מיליטאריה, מיליטריה