The rechargeable battery (with the included USB cable) is my favorite feature. It keeps the unit lightweight in my backpack and on my wallet, since I don't have to buy any batteries. An added bonus is the AUX input that I use to play along to a drum machine.
I've used this amp while wearing headphones and had a fun time. Better still, I rocked out proper by plugging one end of the supplied 3.5mm AUX cable into the headphone jack and the other end into the AUX input of my car stereo, with the volume cranked as loud as possible! Practice is fun again.










