# Constants (/themes/sdk/reference/listing/constants)

```ts
import { … } from '@poltura/theme-sdk/listing';
```

## `collectionRegions` [#collectionregions]

The collection template's regions, where merchants place the listing's blocks.

```ts
const collectionRegions: {
    readonly head: 'head';
    readonly aside: 'aside';
    readonly main: 'main';
}
```

**Example**

```tsx
import { Slot } from '@poltura/theme-sdk/elements';
import { collectionRegions } from '@poltura/theme-sdk/listing';

export function ListingAside() {
  return <Slot name={collectionRegions.aside} />;
}
```