# Instance Handles

Shake instance handles can control shakes after they have been triggered. This is particularly useful to control [Endless Shakes](/shakefx/core/endless-shakes.md) (shakes where the **Duration** is set to **Force** instead of **Impulse**).

## Obtaining the handles

Handles are provided to the user when calling `Shake()` methods on ShakeFX components.

{% hint style="info" %}
**ShakeFX Source** components will return a list of handles, one for every **ShakeFX Listener** component that is active in the scene. This handles the [Multi-Camera](/shakefx/core/multi-camera.md) scenario.
{% endhint %}

## Using the handles

A handle supports the following operations:

* `Target`: Gets the target of the shake (the specific listener or component)
* `SetStrengthMultiplier(float strengthMultiplier)`: Sets a strength multiplier. Ex to manually fade a shake in/out, or to drive it based on gameplay (ex based on player sprint speed).
* `Stop()`: Stops all shake instances in this handle, allowing them to fade-out gracefully.
* `StopImmediately()`: Stops all shake instances in this handle immediately without fading out.
* `QueryState(ShakeState state, QueryFilter filter = QueryFilter.All)`: Queries whether the shake instances in this handle match the specified state.

#### QueryState

A shake asset can have multiple shake definitions, so a handle can point to multiple shake instances internally. This is why `QueryState`  exposes a filter option.

<figure><img src="/files/HHyFj8aSzmFKxHvqzMuT" alt="" width="375"><figcaption><p>A multi-shake asset</p></figcaption></figure>

`ShakeState` can be `FadingIn`, `Holding`, `FadingOut`, or `Finished`.

`QueryFilter` can be:

* **Any:** The query returns true if at least one shake instance matches the query.
* **All:** The query returns true only if every shake instance matches the query.

For example to query if the shake is completely finished the operation would be: `QueryFilter(ShakeState.Finished, QueryFilter.All)`.


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