Swig - Duty Calls Cooler Bag (Assorted Sizes)Swig Life's Tri Cool technology features triple layer construction for maximum insulation: This unique heavy duty, yet lightweight, exterior pvc coated polyester shell provides superior temperature barrier that is waterproof, wipeable and puncture resistant. Topped off with our unique air tight zipper that keeps warm air out, where it belongs! Extra thick closed cell foam insulation surrounds the interior walls and provides twice the temperature