The bag is last year's Clam, it looks like there will be a new model this year. I put a dbl bottom on it, the bottom is where the black box is mounted and the top everything else. There is room to stack 2 12ah bats but since I'm using sla battery I only want the weight of one. When sitting inside my shack I'll hook it up to my battery box with 2 12ah sla's, it seems one bat should last 5-6 hrs. I haven't officially weighed the pack yet but would guess around 18lbs.