I picked this thing up for 250 bucks with the large 4.0 lithium battery from home depot. I initally bought it because i needed another charger and this was only another 70 bucks than the regular milwaukee charger. It charges the batteries and the battery also powers the radio when its unplugged. Am/fm, bluetooth, aux port and a usb port to charge the phone. The big battery fully charged with my phone plugged in and it pretty much on full blast lasted 10 hours. And the battery only takes about and hour to fully charge from dead. Its not to big and its pretty loud and the biggest selling point, theres a bottle opener.