ISO 6743-99:2002建立了一个通用分类系统，适用于以前缀字母“L”指定的润滑剂、工业用油和相关产品。 在L类中，根据每个产品的应用领域，定义了18个产品系列，以便尽可能涵盖使用润滑剂、工业用油和相关产品的所有应用。 ISO 6743的其他部分给出了每个系列的详细分类。 该分类仅适用于新产品。

ISO 6743-99:2002 establishes a general system of classification, which appliies to lubricants, Industrial oils and related products, designated by the prefix letter "L". Within class L, 18 families of products are defined, according to the application areas of each, so as to cover, as much as possible, all the applications where lubricants, industrial oils and related products are used. The detailed classification of each family is given in other parts of ISO 6743. The classification only applies to new products.