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# CBMutableCharacteristic

A characteristic of a local peripheral’s service.

```
class CBMutableCharacteristic
```

## Overview

[`CBMutableCharacteristic`](/documentation/CoreBluetooth/CBMutableCharacteristic) objects represent the characteristics of a local peripheral’s service. This class adds write access to many of the properties in the [`CBCharacteristic`](/documentation/CoreBluetooth/CBCharacteristic) class, which it inherits from.

You use this class to create a characteristic and to set its properties and permissions as desired. After you create and add a characteristic to a local service, you can publish it (and the service) to the peripheral’s local database with the [`add(_:)`](/documentation/CoreBluetooth/CBPeripheralManager/add(_:)) method of the [`CBPeripheralManager`](/documentation/CoreBluetooth/CBPeripheralManager) class. After you publish a characteristic, Core Bluetooth caches the characteristic and you can’t make changes to it.

## Topics

### Creating a Mutable Characteristic

[`-  initWithType:properties:value:permissions:`](/documentation/CoreBluetooth/CBMutableCharacteristic/init(type:properties:value:permissions:))

Creates a mutable characteristic with specified permissions, properties, and value.

### Managing a Mutable Characteristic

[`value`](/documentation/CoreBluetooth/CBMutableCharacteristic/value)

The value of the characteristic.

[`descriptors`](/documentation/CoreBluetooth/CBMutableCharacteristic/descriptors)

An array of the characteristic’s descriptors.

[`properties`](/documentation/CoreBluetooth/CBMutableCharacteristic/properties)

The properties of the characteristic.

[`permissions`](/documentation/CoreBluetooth/CBMutableCharacteristic/permissions)

The permissions of the characteristic value.

[`CBAttributePermissions`](/documentation/CoreBluetooth/CBAttributePermissions)

Values that represent the read, write, and encryption permissions for a characteristic’s value.

[`subscribedCentrals`](/documentation/CoreBluetooth/CBMutableCharacteristic/subscribedCentrals)

A list of centrals that are currently subscribed to the characteristic’s value.

## Relationships

### Conforms To

[`CVarArg`](/documentation/Swift/CVarArg)

[`NSObjectProtocol`](/documentation/ObjectiveC/NSObjectProtocol)

[`CustomStringConvertible`](/documentation/Swift/CustomStringConvertible)

[`Equatable`](/documentation/Swift/Equatable)

[`Hashable`](/documentation/Swift/Hashable)

[`CustomDebugStringConvertible`](/documentation/Swift/CustomDebugStringConvertible)

### Inherits From

[`CBCharacteristic`](/documentation/CoreBluetooth/CBCharacteristic)

---

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