agree with snowreefer.best thing i read so far and i had posted on one of my threads and from some experience,take a cheap thermos,from like the dollar store or something,get some heat packs if its cold out and there u go.im not sure if the heat packs go inside the thermo or outside.but what i would do is take the heat packs and ducktape them to the thermos.oh yeah and stick a damp paper towel with inside the thermos to with the zoas.dont worry about filling it with water just a damp paper towel will work.