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# AudioUnitElement

The data type for an audio unit element identifier.

```
typealias AudioUnitElement = UInt32
```

## Discussion

An audio unit element is a discrete programmatic context that is nested within an audio unit scope (see [`AudioUnitScope`](/documentation/AudioToolbox/AudioUnitScope)). In the context of input and output scopes, elements serve as programmatic analogs of physical signal buses in hardware audio devices. Because of this analogy, the term “bus” is a common synonym for “element.”

Elements are zero indexed. The Global scope always has exactly one element—element 0.

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