Our corrugated shipping boxes (or corrugated shipping container) offer the best durability at the best prices and are perfect for every move. Corrugated boxes (or corrugated fiberboard) are comprised of a heavy paper medium, which is the wavy fluted inner material, and layers of linerboard glued to either side. The linerboard is the flat outer surface. Both the fluted medium and the linerboard are made of a heavy duty paper called containerboard . The strength of a corrugated box will vary depending on the different combinations of mediums and linerboards.