These shadow cards work with the Magnetic Card Reader (sold separately). Prevent unauthorized people from entering buildings or rooms with a keyless access control system that only unlocks when it recognizes an authorized user's driver's license, credit card, ATM card or any other card with a magnetic stripe! Up to 100 authorized users (expandable to 1,000) can unlock the door with a single swipe of a pre-designated card. No keys or PINs required! Rated for over one million card swipes What's Included # 250 Additional Shadow Cards for Magnetic Card Reader The system is perfect for protecting homes, businesses or institutional buildings (i.e. clinics, schools, museums, etc.). It installs onto any door equipped with an electromagnetic lock or doorstrike (sold separately). Programming individual cards takes just seconds! You can also de-activate cards just as fast, in the event an authorized user loses a card, or if you decide to deny access at a later date (i.e. a fired employee).