# isPrimary A Boolean value that indicates whether the type of service is primary or secondary. ``` var isPrimary: Bool { get } ``` ## Discussion A peripheral’s service is either primary or secondary. A primary service describes the primary function of a device. A secondary service describes a service that’s relevant only in the context of another service that references it. For example, the primary service of a heart rate monitor may be to expose heart rate data from the monitor’s heart rate sensor. In this example, a secondary service may be to expose the sensor’s battery data. If the value of this property is , the type of service is primary. If the value of this property is , the type of service is secondary. --- 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)