Abstract: A precursor for forming a spacer and the spacer itself for protecting and holding a window frame within a carton or container. The window frame includes a flange. The precursor is a generally planar blank of corrugated paper having plural fold lines to facilitate the folding of the blank to form the spacer. The spacer has an elongated body having a first side and a second side opposed to each other. The first side includes a recess formed by confronting portions of the blank and is arranged to receive a portion of the flange of the window frame therein. The second side of the elongated spacer body is arranged to closely engage an adjacent interior surface of the carton or container.