Cardboard is a thick paper product that has a corrugated multilayer structure. It is mainly used as a packing material, protective material, cushioning material, and fixing material when transporting and storing goods. A rectangular parallelepiped box is generally used, but there are also types such as those that are thick cushion layers, those that are rolls used by cutting the required size, and those that are square tubes that can be enclosed a large poster or document wrapped. In addition, there are many related products such as a holder that temporarily holds the lid of the cardboard box during packing work, a clip that can temporarily close the lid that has been opened, a carry handle that can be attached to the side of the box for handheld packaging, a cutter that assists in unpacking. Most of the cardboard is a simple shade such as light brown craft color or white, and features a design that emphasizes practicality.