Features:

The factory setting is slave mode, but you can set this module to master mode so that you might be able to connect to other Bluetooth 2.0 devices.HC-05 Wireless BT Module
HC-05 Wireless BT Module: with this HC 05 Bluetooth module,You can quickly add the Bluetooth feature to your Arduino project, and then you can use your android phone to control some gadgets, such as: switch, LED.
Master and Slave 2-IN-1 HC 05 Module:Working Voltage 3.6V to 6V , Default baud rate:9600,Default pin:1234
Button: Press the button, the module enter the AT mode. AT commands are executed only in AT mode