# WstEthReserveOracle

[Git Source](https://github.com/Ion-Protocol/ion-protocol/blob/88cc595825f1dc2eb738fb93e172a3e8ab7a5c43/src/oracles/reserve/lst/WstEthReserveOracle.sol)

**Inherits:** ReserveOracle

Reserve oracle for wstETH.

### [State Variables](https://docs.ionprotocol.io/devs/smart-contract-architecture/oracles/reserve/lst/broken-reference) <a href="#state-variables" id="state-variables"></a>

#### [WST\_ETH](https://docs.ionprotocol.io/devs/smart-contract-architecture/oracles/reserve/lst/broken-reference) <a href="#wst_eth" id="wst_eth"></a>

```
address public immutable WST_ETH;
```

### [Functions](https://docs.ionprotocol.io/devs/smart-contract-architecture/oracles/reserve/lst/broken-reference) <a href="#functions" id="functions"></a>

#### [constructor](https://docs.ionprotocol.io/devs/smart-contract-architecture/oracles/reserve/lst/broken-reference) <a href="#constructor" id="constructor"></a>

Creates a new `WstEthReserveOracle` instance.

```
constructor(
    address _wstEth,
    uint8 _ilkIndex,
    address[] memory _feeds,
    uint8 _quorum,
    uint256 _maxChange
)
    ReserveOracle(_ilkIndex, _feeds, _quorum, _maxChange);
```

**Parameters**

| Name         | Type        | Description                                                    |
| ------------ | ----------- | -------------------------------------------------------------- |
| `_wstEth`    | `address`   | wstETH contract address.                                       |
| `_ilkIndex`  | `uint8`     | of wstETH.                                                     |
| `_feeds`     | `address[]` | List of alternative data sources for the WstEth exchange rate. |
| `_quorum`    | `uint8`     | The amount of alternative data sources to aggregate.           |
| `_maxChange` | `uint256`   | Maximum percent change between exchange rate updates. \[RAY]   |

#### [\_getProtocolExchangeRate](https://docs.ionprotocol.io/devs/smart-contract-architecture/oracles/reserve/lst/broken-reference) <a href="#getprotocolexchangerate" id="getprotocolexchangerate"></a>

Returns the exchange rate between wstETH and stETH.

*In a slashing event, the loss for the staker is represented through a decrease in the wstETH to stETH exchange rate inside the wstETH contract. The stETH to ETH ratio in the Lido contract will still remain 1:1 as it rebases. stETH / wstETH = stEth per wstETH ETH / stETH = total ether value / total stETH supply ETH / wstETH = (ETH / stETH) \* (stETH / wstETH)*

```
function _getProtocolExchangeRate() internal view override returns (uint256);
```