How is it powered?
According to the product page at the mothership (http://www.amazon.com/iSunnao-Bluetooth-Wireless-Music-Receiver/dp/B0164F9PUK) it has a battery. One of the reviews mentions that it has a microUSB slot for charging.
Battery lifetime up to 8 hours.
How is the interference with these?
I like the idea. The cigarette lighter models too, but keep reading about how the transmission causes nasties.
will allow you to make hands free calls using bluetooth?