# Exposure Parameter Limits The limits for the parameters you use in exposure risk calculations. ## Topics ### Enumerations [Attenuation](/documentation/ExposureNotification/attenuation) The minimum and maximum signal attenuations. [Risk Level](/documentation/ExposureNotification/risk-level) The minimum and maximum risk levels. [Risk Level Value](/documentation/ExposureNotification/risk-level-value) The minimum and maximum risk level values. [Risk Score](/documentation/ExposureNotification/risk-score) The minimum and maximum risk score. [Risk Weight](/documentation/ExposureNotification/risk-weight) The minimum, default, and maximum risk weights. [`struct ENActivityFlags`](/documentation/ExposureNotification/ENActivityFlags) Activities that occur while the app isn’t running. [`enum ENCalibrationConfidence`](/documentation/ExposureNotification/ENCalibrationConfidence) The transmitting device’s calibration confidence. [`enum ENDiagnosisReportType`](/documentation/ExposureNotification/ENDiagnosisReportType) The type of a report that describes the origin of a diagnosis. [`enum ENInfectiousness`](/documentation/ExposureNotification/ENInfectiousness) The degree to which a person’s symptoms may indicate transmission risk. ### Enumerations [`struct ENActivityFlags`](/documentation/ExposureNotification/ENActivityFlags) Activities that occur while the app isn’t running. [`enum ENCalibrationConfidence`](/documentation/ExposureNotification/ENCalibrationConfidence) The transmitting device’s calibration confidence. [`enum ENDiagnosisReportType`](/documentation/ExposureNotification/ENDiagnosisReportType) The type of a report that describes the origin of a diagnosis. [`enum ENInfectiousness`](/documentation/ExposureNotification/ENInfectiousness) The degree to which a person’s symptoms may indicate transmission risk. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)