item
Item represents file used in eBook.

Example: 

<item id="content" href="contents.htm" media-type="text/x-oeb1-document" />

attributes

id
Provides an element with a unique name within a single document. This is especially useful in works with extensive cross-referencing and linking, such as dictionaries, encyclopedias, or travel guides. Use of ids  simplifies linking and updates.
class
Affiliates an element with one or more classes.
style
Attaches a list of inline (name:value paired) CSS properties to a specific tag, for example: style="name:value;name:value"
href
File URI
fallback
Identifier
media-type
Text or image media type. Texts: text/x-oeb1-document. Images: image/jpeg, image/png, image/gif

See also:

<manifest>