---
title: HKMetadataKeyHeadphoneGain
framework: healthkit
role: symbol
role_heading: Global Variable
path: healthkit/hkmetadatakeyheadphonegain
---

# HKMetadataKeyHeadphoneGain

## Declaration

```swift
let HKMetadataKeyHeadphoneGain: String
```

## See Also

### Audio Event Keys

- [HKMetadataKeyAudioExposureLevel](healthkit/hkmetadatakeyaudioexposurelevel.md)
- [HKMetadataKeyAudioExposureDuration](healthkit/hkmetadatakeyaudioexposureduration.md)