Electronic Article Surveillance (EAS) is a security system used in retail stores to prevent theft. It typically involves tags or labels attached to merchandise that trigger an alarm if someone tries to leave the store without paying. These tags can be deactivated or removed at the checkout. The EAS system consists of three main components: tags, detectors, and deactivators. Tags are placed on items, detectors are positioned at store exits, and deactivators are used at the register. When a customer pays for an item, the cashier deactivates the tag, allowing the customer to exit without setting off the alarm.