>>99813125 amp-hour deep-cycle marine battery in a box. I've since bolted a 5A tender to the front of the enclosure. Cig lighter output on top.
Works awesome for priming fuel pumps in the garage, charging phones/cameras/radios that need 12v, running radios, jumpstarting vehicles, etc. Also plug it into my trailer and run furnace/lights off it. Enough capacity to keep the furnace going all day when i'm out snowmobiling.
That particular photo is a Mini-B car charger that's charging my helmet camera.