Abstract: An extendable pole or mast is constructed from a plurality of nested pole sections with each pole section is made from an initially flat sheet which is roll formed into a rectangular, preferably square, cross section element. A seam is formed by over lapping the edges of the sheet, with the bulk of the seam being placed inwardly of the element. Each of the inner sections includes its own seam and an offset of sufficient size and depth to receive the seam and offset of an outer sections. The sheet material permits tabs to be cut or stamped into outer walls of the outer sections in order to support an adjacent inner pole section. Tabs are formed in each of the outer pole sections. These tabs are biased to extend inwardly, against the adjacent inner pole section. Tabs may be formed below the first tab to provide a choice in the amount of extension of the pole.