> For the complete documentation index, see [llms.txt](https://docs.kpk.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.kpk.io/funds/infrastructure/onchain-accounting/price-feeds/eeth.md).
# eETH
eETH is Ether.fi's rebasing staked-ETH token (weETH is its non-rebasing wrapper). Because eETH is a \~1:1 rebasing claim on staked ETH, its fundamental (redeemable) value tracks ETH one-for-one, so it is priced **directly off the NAV's ETH/USD** — `eETH/ETH ≡ 1.0`. Any market divergence is surfaced by a market **monitor** feed, not by moving this price.
**Source:** [`eETH_CustomPriceFeed.sol`](https://github.com/karpatkey/onchain-accounting/blob/main/src/prices/protocols/eETH_CustomPriceFeed.sol)
***
## Approach
`1.0 × ETH/USD` — this is a pure-fundamental [`BaseCustomPriceFeed`](/funds/infrastructure/onchain-accounting/price-feeds.md#supported-feed-types) subclass whose `_rate()` hook returns the constant `1e18` (eETH/ETH ≡ 1.0), so the price is exactly the NAV's ETH/USD. The old feed back-derived eETH/ETH from the weETH/ETH Chainlink feed and `weETH.getRate()`; that market leg is gone. The ETH/USD term is the NAV's own price for WETH (via `getPriceDataNoDivergence(WETH)`), not a hardcoded oracle.
eETH price feed — a constant unit rate (eETH/ETH ≡ 1.0) scaled by the NAV's ETH/USD, with the staleness gate.
{% hint style="info" %}
The ETH/USD term is sourced from the NAV's own primary feed — see [Base/USD from the NAV's own selector](/funds/infrastructure/onchain-accounting/price-feeds.md#base-usd-from-the-navs-own-selector).
{% endhint %}
***
## Price calculation
```
price = 1e18 (18) × (ETH/USD, NAV-selected) (8) / 1e18 // USD, 8 dec — i.e. price = ETH/USD
```
| Input | Source | Description |
| ------- | -------------------------------------------------- | ---------------------------------- |
| rate | constant `1e18` (eETH/ETH ≡ 1.0) | 1 eETH is redeemable \~1:1 for ETH |
| ETH/USD | **NAV** — `getPriceDataNoDivergence(WETH)` (8 dec) | the NAV's primary WETH/USD price |
Output decimals are inherited from the ETH/USD feed (8).
***
## Constructor
```solidity
constructor(
address eEth_,
address nav_,
address baseAsset_
)
```
| Parameter | Description |
| ------------ | ------------------------------------------------------------------------------------------ |
| `eEth_` | eETH token address (the supported underlying) |
| `nav_` | NAVCalculator (proxy) — supplies the base asset's USD price via `getPriceDataNoDivergence` |
| `baseAsset_` | the registered base asset whose USD price is the eETH price (WETH) |
***
## Staleness
`getLatestPrice()` returns stale only if the NAV reports the base asset (WETH) primary feed stale — the rate is a constant, so there is no rate call or heartbeat to gate. The reported `updatedAt` comes from the NAV's selected WETH feed.
***
## Divergence monitors
A market **monitor** feed can be attached to flag a real eETH depeg via NAVCalculator's divergence check; on Ethereum mainnet eETH currently ships with no monitor (no divergence tolerance set). See [Primary feed and divergence monitors](/funds/infrastructure/onchain-accounting/price-feeds.md#primary-feed-and-divergence-monitors).
***
## Chains
Deployed on **Ethereum**.
---
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