dicks sporting goods or ebay.. If its an air tight seal ie a good styofoam container with a lid, and its sealed with tape all the way around a 10 hour pack will keep the water warm for up to 24 hours. i've shipped with 10 hour heat packs before and they have kept the water warm enough for 24 hours. I dont advise it, but it has worked for me when i didnt have time to order 24 hour heat packs. But the key once again is a good container with an air tight seal.
