Cooler Shock ice packs are a cooling alternative that far outperforms ice, saving weight and space. Cooler Shock comes in large, mid-size or small packs. You can buy them ready to use or in DIY form that lets you fill with water and then seal them. Sealing is done with a simple cork and screw cap or a zipper version followed by an iron for a permanent seal. Dry cooler packs are a great value and tremendously popular. Cooler Shock is a gel when warm and a solid block when frozen. The packs can actually freeze room temperature water over a 4 hour period. Warm drinks turn ice cold and sandwiches won't be soggy at the end of the day. Ice packs go back in the freezer for your next outing. Use for boating, fishing, picnics, tailgating and transporting perishable goods. Cooler Shock ice packs have over 2500 "5-Star" reviews on Amazon with uses running the gamut from commercial food transport to keeping pets cool. There are also documented tests against ice.