Shells are the preprinted brochures with photos, illustrations, and graphics but no text; also
called slicks.
Other definition:
Shells are a marketing and sales promotional piece that depicts a destination, accommodation or attraction on the cover and provides space for copy to be added at a later date. Usually shells fit a #10 envelope.
Other definition:
Shells are the preprinted brochures with photos, illustrations, and graphics but no text; also called slicks.
The Travel-Glossary: Everything about Travelling, Sightseeing and the World.