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# id

A unique, stable identifier for a device.

```
let id: String
```

## Discussion

Provide this identifier when you create an [`ElectricalLoadDevice`](/documentation/EnergyKit/ElectricalLoadDevice) instance for submitting electrical load events. The EnergyKit framework uses this identifier to associate events with devices and generate device-specific insights.

The system expects the value to be a maximum of 64 UTF-8 characters, such as a UUID. Ensure the identifier:

- Isn’t empty, and is less than or equal to 64 characters
- Uses only alphanumeric, space, hyphen, and apostrophe characters
- Starts and ends with an alphanumeric character

---

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