What do we usually mean by 250 grams of grey board?Many customers may misinterpret it as referring to the weight of a sheet of grey board. In fact, the weight of a sheet of grey board refers to the weight of a sheet of paper per unit area.Overseas also has with each ream paper how many pound or how many kilograms are represented, can convert according to the length of paper, width and each ream sheet number into each square metre how many grams.Therefore, the paper by weight to calculate the price of sales.But domestic grey board, usually there is a deviation, so the goods on the market are rarely by weighing way to acceptance, which is based on the domestic .