I think size and weight do not match, unless it is something fancy, which, given the other equipment quality, I guess it's not. They probably would not waste a non-rechargeable battery to refrigerate their food, so... a TL7 pickup truck's lead-acid battery? Will weigh 40 pounds and fit in a small backpack, more or less filling it. Let us approximate it with a Very Large Rechargeable Battery from HT13. Nominal 20*8*5 = $800. Hooked up to an inverter costing about as much? Or is it some sort of a portable fridge? I think portable one would be too small. Let's see... 20 men * 3 meals * 3 days of refrigirated food would be about 180 pounds. It they have more, a good chunk should be dried or canned. We'll see if we can cram some of it into cars. While we are hauling the first load of stuff to the surface, what loot do the men there report? Also, can we haul the fridge out? A TL7 or TL8 thing with maybe some conditions?