# RefIdNull

> Special value, -2, used as the managed reference Id of any field decorated with SerializeReference that has no object assigned to it.

## Definition

* **Type:** Field
* **Namespace:** [UnityEngine.Serialization](/engine/6000.6/script-reference/unityengine/serialization.md)
* **Assembly:** UnityEngine.CoreModule

```csharp
public const long RefIdNull = -2
```