# seriesType(forIdentifier:) Returns the shared series type for the provided identifier. ``` class func seriesType(forIdentifier identifier: String) -> HKSeriesType? ``` ## Parameters `identifier` A series type identifier. In iOS 11 and watchOS 4, there is only one series type identifier: [`HKWorkoutRouteTypeIdentifier`](/documentation/HealthKit/HKWorkoutRouteTypeIdentifier). ## Return Value The shared [`HKSeriesType`](/documentation/HealthKit/HKSeriesType) instance based on the provided identifier. ## Discussion This method returns an instance of the [`HKSeriesType`](/documentation/HealthKit/HKSeriesType) concrete subclass. HealthKit uses series types to represent samples that store a series of items. You can’t directly instantiate these samples; instead, use a [`HKSeriesBuilder`](/documentation/HealthKit/HKSeriesBuilder) subclass to create them. Use series types to ask for permission to read series data from the HealthKit store. ## See Also [`class func workoutRoute() -> Self`](/documentation/HealthKit/HKSeriesType/workoutRoute()) Returns a series type object for workout routes. [`class HKWorkoutRoute`](/documentation/HealthKit/HKWorkoutRoute) A sample that contains a workout’s route data. [`class HKWorkoutRouteBuilder`](/documentation/HealthKit/HKWorkoutRouteBuilder) A builder object that incrementally constructs a workout route. --- 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)