---
title: "subscribeAttributeRmsVoltageSagPeriodPhaseB(with:subscriptionEstablished:reportHandler:)"
framework: matter
role: symbol
role_heading: Instance Method
path: "matter/mtrbaseclusterelectricalmeasurement/subscribeattributermsvoltagesagperiodphaseb(with:subscriptionestablished:reporthandler:)"
---

# subscribeAttributeRmsVoltageSagPeriodPhaseB(with:subscriptionEstablished:reportHandler:)

## Declaration

```swift
func subscribeAttributeRmsVoltageSagPeriodPhaseB(with params: MTRSubscribeParams, subscriptionEstablished: MTRSubscriptionEstablishedHandler?, reportHandler: @escaping (NSNumber?, (any Error)?) -> Void)
```