Here's a fully featured stereo Bluetooth v4.2 module. Output USB, SD card, or Bluetooth audio over its 3W amplifiers.
This fully featured bluetooth board packs a punch in a small package. Not only can you stream audio over Bluetooth, you can play music off of a USB drive or SD card, output audio over a headphone jack or L/R amplifiers, and control the board functions with an included IR remote or button interface (must be implemented separately).
Bluetooth version: the bluetooth version is 4.2. It can be compatible with all mobile phone and bluetooth adapters on the market. The distance is about 15 meters. Supports automatic return of paired devices and automatically broadcasts music. When connecting to the board through bluetooth, XY_BT is the name of the device.
You can also power this with a lithium polymer battery to make it completely portable!
Note: Do NOT attempt to "mono sum" the speaker outputs. They are individual amplifier chips and "summing" will cause damage. To maximize the range, the integrated Bluetooth antenna should not be close to metal parts.