---
title: CBAdvertisementDataTxPowerLevelKey
framework: corebluetooth
role: symbol
role_heading: Global Variable
path: corebluetooth/cbadvertisementdatatxpowerlevelkey
---

# CBAdvertisementDataTxPowerLevelKey

The transmit power of a peripheral.

## Declaration

```swift
let CBAdvertisementDataTxPowerLevelKey: String
```

## Discussion

Discussion The value associated with this key is an instance of NSNumber. This key and value are available if the peripheral provides its transmitting power level in its advertising packet. You can calculate the path loss by comparing the RSSI value with the transmitting power level.

## See Also

### Advertisement Keys

- [CBAdvertisementDataLocalNameKey](corebluetooth/cbadvertisementdatalocalnamekey.md)
- [CBAdvertisementDataManufacturerDataKey](corebluetooth/cbadvertisementdatamanufacturerdatakey.md)
- [CBAdvertisementDataServiceDataKey](corebluetooth/cbadvertisementdataservicedatakey.md)
- [CBAdvertisementDataServiceUUIDsKey](corebluetooth/cbadvertisementdataserviceuuidskey.md)
- [CBAdvertisementDataOverflowServiceUUIDsKey](corebluetooth/cbadvertisementdataoverflowserviceuuidskey.md)
- [CBAdvertisementDataIsConnectable](corebluetooth/cbadvertisementdataisconnectable.md)
- [CBAdvertisementDataSolicitedServiceUUIDsKey](corebluetooth/cbadvertisementdatasolicitedserviceuuidskey.md)