This interactive guide to the heavens displays the position of the stars for any hour, of any day, of any year. Simply align the time of day and the day of the year on the rotating dials, and the sky window displays exactly how the sky will appear at that time. PRODUCT DETAILS Sizes: 5.50″ and 10.5″ Materials: White plastic base dial and clear plastic top dial. Storage Pouch: Durable vinyl pouch with clear front.