Biometric sensors are devices that measure and recognize an individual's physical characteristics for authentication purposes. They are typically used for authentication and access control systems, often in combination with other authentication methods such as passwords, PINs, and tokens. Common forms of biometric sensors include fingerprint scanners, retinal scanners, facial recognition systems, and voice recognition systems. These sensors compare a person's physical features with a stored template to identify and validate the individual themselves. This technology helps to ensure secure access to restricted areas, restricted access to sensitive data, and increased data integrity.