Abstract: An extendable shelf comprises a first shelf extension and a second shelf extension slidingly engaged to permit extension to a variety of widths. Stops mounted at predetermined locations to provide specific widths of the assembled shelf. An indicia sheet is carried by the first shelf extension. The indicia sheet is marked with a plurality of indicia to indicate the different potential widths of the assembled shelf. A cover sheet is carried by the second shelf extension. Lateral adjustment of the shelf extensions to different relative positions causes the cover sheet to exposes appropriate indicia to identify the current shelf width and covers the alternative indicia of widths.