# Sandbox.UI.LengthUnit.Undefined

```csharp
static LengthUnit Undefined
```

Similar to CSS 'unset', basically means we don't have a value; should only really be used under certain
circumstances (e.g. to handle background sizing properly).

Declared in [Sandbox.UI.LengthUnit](/api/Sandbox.UI.LengthUnit).
Assembly: `Sandbox.System`.