# Header Subquery

## Description

The Header Subquery provides information about a past block's nonce, header, gasLimit, etc.&#x20;

## Limits

Maximum of 32 Header subqueries per Query.

## Builder

`buildHeaderSubquery(blockNum)`

## Examples

```typescript
const headerSubquery: HeaderSubquery = buildHeaderSubquery(8000000)
    .field(HeaderField.ParentHash);
```

```typescript
const headerSubquery: HeaderSubquery = buildHeaderSubquery(8000000)
    .field(HeaderField.GasUsed);
```

```typescript
const headerSubquery: HeaderSubquery = buildHeaderSubquery(8000000)
    .logsBloom(3); // logs bloom filter at 3rd bytes32 chunk
```
