This is a very useful Gadget. It is used to connect any speaker to Bluetooth
You can find a list of the best bluetooth speaker at the bottom (UE Boom 2. Fugoo Style, JBL Charge 3, Bowers and Wilkins Zeppelin Wireless, Bose SoundLink Mini II, UE Wonderboom, Creative Muvo 2C, Bang and Olufsen Beoplay P2)
You power it up with a battery. You can use three or four batteries 18650. you connect the green plugs to the speaker entry. You can then play music from your mobile phone into your big speaker in this becomes a mobile speaker
JBL Charge 3.
Bowers and Wilkins Zeppelin Wireless.
Bose SoundLink Mini II.
Creative Muvo 2C.
Bang and Olufsen Beoplay P2