A “reference” means the version of a product whose units all share the same technical characteristics, such as colour, material composition, shape and texture, excluding size variations. This term may correspond to the concept of a stock keeping unit (SKU; UGS in French) or a colour reference. It may take the form of a series of letters or numbers shown on the product page, corresponding to a given colour of a given product. A reference may be available in several sizes. In that case, only one reference is counted for all the sizes offered. Certain references may specifically concern certain sizes: this is the case, for example, for plus sizes. Only references corresponding to clothing textiles must be counted. Shoes or bags, for example, must not be counted.