---
title: "hertzUnit(with:)"
framework: healthkit
role: symbol
role_heading: Type Method
path: "healthkit/hkunit/hertzunit(with:)"
---

# hertzUnit(with:)

Returns a HealthKit unit for measuring frequency in hertz with the provided prefix.

## Declaration

```swift
class func hertzUnit(with prefix: HKMetricPrefix) -> Self
```

## Parameters

- `prefix`: A valid metric prefix value. For the complete list of prefix values, see doc://com.apple.healthkit/documentation/HealthKit/HKMetricPrefix.

## Discussion

Discussion Hertz represent cycles per second.

## See Also

### Constructing frequency units

- [hertz()](healthkit/hkunit/hertz().md)