The mall specializes in producing and selling high-purity experimental products for "scientific research institutes, universities and other" scientific research institutions and laboratories. For experiments, we should buy high-cost and high-purity products instead of low-cost and low-purity products. We should buy according to the actual use. Although the purity of industrial products looks the same. We should avoid low purity industrial products entering the laboratory, which will affect the accuracy of experimental results. In this scheme, 1000mm-100mm-0.01mm is equivalent to the size of stainless steel foil with length of 1000mm, width of 100mm and thickness of 0.01mm. Other specifications in the option have the same meaning.