No, the size they sell (atleast where i used to get it in Antlers)fits perfect in the bottom of the chest. I get 5 and line them side by side. Put pop/beer, etc on top, then cover with bag ice.
Hmmmm ... we do that with the cold packs that come with GC's meds. Line the bottom and sides of the ice chest and then dump ice on top. When we get back home I just pop them back in the freezer for next time.