The Igloo Playmate is so relatively inexpensive, the "dry ice" lifespan of a year or so is actually pretty good - especially as opposed to using disposable fiberboard shipping boxes. We use Igloo products with dry ice routinely - however, we use dry ice pellets, NOT the more common sliced blocks. I can't remember for certain off the top of my head, but I think the Igloo Playmate validated for 12 hours under a "normal use" environment, packed with 10 FFP units and about 3 pounds of dry ice pellets. (Our procedure limits staff to 8 hours of transit time). Hope this helps. -robert