Marketing collateral is a term used for printed materials used to present information about your business and its capabilities, products or services. It can include brochures, fliers, fact sheets, direct mail pieces, and other communications pieces that are produced directly by the company.
http://www.onlinewbc.gov/docs/market/mk_collateral.html

Marketing collateral, in sales, is the collection of media used to support the sales of a product or service. These sales aids are intended to make the salesperson's job easier and more effective. Common examples include:
Sales brochures and other printed product information
Posters and signs
Visual aids used in sales presentations
Web content
Sales scripts
Demonstration scripts
It differs from advertising in that it is used later in the sales cycle, usually when a prospective purchaser has been identified and sales staff are making contact with them.
http://en.wikipedia.org/wiki/Marketing_collateral

Marketing Collateral – Any supporting documentation that provides information about a manufacturer’s product line; i.e. brochures, posters, spec sheets, and product shots are some examples of collateral. Also known as media documentation.
http://www.concise.com/GlossaryofTerms.htm

marketing collateral: the material used to market a product or service as distinct from the documentation which is part of the product
http://www.bena.com/ewinters/Glossary.html