Abstract: A packing bag made of a strong cloth material, combined with a tensioning device which facilitates simple but effective adjustment of the volume of the compressible contents therein. A high degree of compression is achieved by placing two substantially rigid, elongated, stiffening members along the sides of the bag and attaching one or two straps thereto with fasteners. The distance between the stiffening members is controlled by the straps, allowing for the alteration of the volume of the bag. The pressure which appears at compression is divided along the sides of the bag because of the stiffening members, and is not confined to the areas where the straps are attached. The bag can be designed with the opening at either end, thus taking the shape of a cylinder, or with the opening at a wider end, thus taking on a conical shape prior to compression and a cylindrical shape after compression.