I am located in south florida and have been out of power for 3 days and counting now. Prior to hurricane irma arrival I had charged up my stock of 200 18650 batteries. I had power banks that quickly died as our only source of information and communication was our cell phones service which seems stable at the moment and seemed inefficient. However my rx 300 with 4 fresh fullt charged 3000mah lg brownies was a beast when using as a power bank with the adapter. Yes it is big and cumbersome for vaping but a life saver in an emergency situation.