I would have to recommend fat max BLINDLY again i have 2 of the other and it has been by far the most failed device i have ever owned, On a side note Daniel walsh is a nice guy and goes above and beyond with Customer service but the device to me is defective it has a built in fuse that once spikes the unit is dead, A slightly overcharged battery killed my head unit 3 times each time i waited a month for replacement, the charger melted and the cartos supplied didn't fit the device without a adapter, Well they fit but wont fire it. again i have the guys # on my phone and i always said 1 day i would try again because of his customer service but i havent @ free i might tho.. just my experience.. If i take a oring and install between carto and head and use a extension and let battery sit after charging outside the device a bitt it works good.
This is not a bash again just my experience,