Key cards are small, plastic cards that use magnetic stripes or embedded chips to grant access to secure areas, such as hotel rooms or office buildings. They are often used as a convenient alternative to traditional keys, allowing users to unlock doors by simply swiping or tapping the card against a reader. These cards can be programmed to restrict access to specific areas and times, enhancing security. Many modern key cards also include features like RFID technology, which allows for contactless entry. This technology is widely used in various industries, including hospitality and corporate environments, to streamline access control.