EXTRA HARD 3-LAYER CONSTRUCTION: These corrugated cardboard sheets are a 3-ply super rigid structure for strength and durability. This makes them ideal for packaging, shipping, and transportation. FLAT AND SMOOTH SURFACE: The size of the 3mm cardboard sheet is 20 x 30 cm. The cardboard sheet has a flat and smooth surface, and the size is enough to be used for printing, painting, or writing. ECONOMICAL: This brown cardboard rectangle contains 50 packing cardboard sheets, which makes it ideal for those who need a lot of cardboard. In addition, they are relatively inexpensive, making them a very economical choice. VERSATILE USE: These flat cardboard sheets are suitable for a wide range of applications, including DIY projects, crafting, and more. They can be easily cut and shaped to meet your specific needs. WORRY-FREE PURCHASE: If you have any dissatisfaction with our corrugated cardboard sheets within 30 days after receiving the product, you can contact us for a refund. Feel free to email us and let us know if you have any questions or feedback about our product. We are dedicated to providing you a satisfactory shopping satisfaction.