Completely portable, each pack includes a best-selling Berlitz Phrase Book and audiocassette or CD. Audio components are designed to interact with the Phrase Book, or can be used on their own, in a car or on the go.Berlitz Cassette/CD Packs feature: -- One 90-minute cassette or one 75-minute compact disc -- A corresponding 192- or 224-page, color-coded Berlitz Phrase Book to reinforce skills -- Audio recordings with native speakers -- Over 400 recorded essential expressions -- Up-to-date language, cultural tips, and mini dialogues