Access cards are small, portable devices used to gain entry to secure areas, such as buildings or restricted zones. They often contain a microchip or magnetic strip that stores information, allowing users to unlock doors or access systems by swiping or tapping the card against a reader. These cards are commonly used in workplaces, schools, and hotels to enhance security and control who can enter specific locations. They can also be programmed to limit access to certain times or areas, ensuring that only authorized personnel, such as employees or guests, can enter sensitive spaces.