> ## Documentation Index
> Fetch the complete documentation index at: https://docs.restaking.cloud/llms.txt
> Use this file to discover all available pages before exploring further.

# rst sub-class

The following readme describes all the necessary functions and their parameters exposed by the `rst` class of the K2 SDK.

## getDeployer function

Get address of the RST module factory that deployed the RST.

### Input Parameters

rstAddress: Address of RST contract in string

### Using getDeployer function

```javascript theme={null}
await sdk.rst.getDeployer(rstAddress);
```

### Return Parameter

Returns address of RST deployer

## getSBPIndex function

Reference to the unique SBP index in the K2 lending contract where activity can be checked.

### Input Parameters

rstAddress: Address of RST contract in string

### Using getSBPIndex function

```javascript theme={null}
await sdk.rst.getSBPIndex(rstAddress);
```

### Return Parameter

Returns uint256 SBP index in Big Numbers

## updateSBPIndex function

For new SBPs created, the deployer uses this method so that the RST points to the new SBP index.

### Input Parameters

rstAddress: Address of RST contract in string\
newSBPIndex: new SBP index in string

### Using updateSBPIndex function

```javascript theme={null}
await sdk.rst.updateSBPIndex(rstAddress, newSBPIndex);
```

### Return Parameter

Transaction hash

## isActive function

Check if the RST token is active or not.

### Input Parameters

rstAddress: Address of RST contract in string

### Using isActive function

```javascript theme={null}
await sdk.rst.isActive(rstAddress);
```

### Return Parameter

Boolean. `true` if active, `false` otherwise.