Corrugated cardboard primarily consists of pulp material derived from timber, wood chips, and mill waste. It comprises two glued paper sheets, known as liners, with an inner corrugated layer called fluting. This combination creates a stable structure capable of withstanding pressure and weather changes. Corrugated cardboard comes in different types, with the number of layers being the main differentiating factor. Examples include single and double-layer corrugated cardboard. The more layers it has, the greater its stiffness and durability.