of item stored defines its properties. The properties of an Item may be a ScalarType, which defines the smallest unit of information a property can have, or a NestedType, which is a collection of more than one ScalarTypes and/or NestedTypes. All WinFS types are made available as .NET CLR classes . [ 27 ] Any object represented as a data unit, such as contact, image, video, document etc., can be stored in a WinFS store as a specialization of the Item type. [ 27 ] By default, WinFS provides Item types for Files, Contact, Documents, Pictures, Audio, Video, Calendar, and Messages. The File Item can store any generic data, which is stored in file systems as files. But unless an advanced schema is provided for the file, by defining it to be a specialized Item, WinFS will not be able to access its data. Such a file Item can only support being related to other Items. [ 6 ] Defining a new Type A developer can extend any of these types, or the base type Item, to provide a type for his custom data. The data contained in an Item is defined in terms of properties, or fields which hold the actual data. For example, an Item Contact may have a field Name which is a ScalarType, and one field Address , a NestedType, which is further composed of two ScalarTypes. To define this type, the base class Item is extended and the necessary fields are added to the class.