There are different kinds of art exhibitions, in particular there is a distinction between commercial and non-commercial exhibitions. A commercial exhibition or trade fair is often referred to as an art fair that shows the work of artists or art dealers where participants generally have to pay a fee. A vanity gallery is an exhibition space of works in a gallery that charges the artist for use of the space. Temporary museum exhibitions typically display items from the museum's own collection on a particular period, theme or topic, supplemented by loans from other collections, mostly those of other museums. They normally include no items for sale; they are distinguished from the museum's permanent displays, and most large museums set aside a space for temporary exhibitions.