Passport Book vs. Passport Card
The passport card serves the same purpose as a passport book, but can conveniently be placed in your wallet. The card is only valid for use at land border crossings or sea ports-of-entry when entering the United States from Mexico, Canada, the Caribbean, or Bermuda. The passport card cannot be used for international travel by air. The requirements for a passport card are the same as the requirements for a passport book. The card has the same validity period as a passport book: 10 years for an adult and 5 years for minors.