# id

> Uniquely identifies a contact point between two shapes. This should not be confused with PhysicsShape.ContactId.

## Definition

* **Type:** Property
* **Namespace:** [Unity.U2D.Physics](/engine/6000.7/script-reference/unity/u2d/physics.md)
* **Assembly:** UnityEngine.PhysicsCore2DModule

```csharp
public readonly ushort id { get; }
```