# Collapse ## Props | Name | Type | Default | Description | |:-----|:-----|:--------|:------------| | children | node | | The content node to be collapsed. | | classes | object | | Useful to extend the style applied to components. | | in | bool | false | If `true`, the component will transition in. | | onEnter | function | | Callback fired before the component is entering. | | onEntered | function | | Callback fired when the component has entered. | | onEntering | function | | Callback fired when the component is entering. | | onExit | function | | Callback fired before the component is exiting. | | onExited | function | | Callback fired when the component has exited. | | onExiting | function | | Callback fired when the component is exiting. | | transitionDuration | union: number
 string
| 300 | Set to 'auto' to automatically calculate transition time based on height. | Any other properties supplied will be spread to the root element. ## CSS API You can overrides all the class names injected by Material-UI thanks to the `classes` property. This property accepts the following keys: - `container` - `entered` Have a look at [overriding with class names](/customization/overrides#overriding-with-class-names) section for more detail. If using the `overrides` key of the theme as documented [here](/customization/themes#customizing-all-instances-of-a-component-type), you need to use the following style sheet name: `MuiCollapse`.