Service products can provide consumers with the same use value as tangible products, but it is different from tangible products, and its characteristics are intangible, artificial and non-storable.

Generally speaking, the products provided by production enterprises appear in front of consumers in a certain physical form during the sales process. Consumers can choose and evaluate library service products according to their appearance, shape, taste and other characteristics, otherwise it is an abstract activity that can't be seen, touched, smelled or obtained, which is the invisibility of library service products.