RB28 is a 28 ounce brick that is 7"x5"x1.5". If you need a way to keep your food cold or frozen, these blocks of rigid foam will do the job for up to 2-3 days. They are reuseable, non-toxic, and rated the best in foam refrigerants. They prevent thawing or keep frozen foods chilled for an extended period of time. You can also use them to protect against freezing. When packaged in properly insulated containers, warmed RE-FREEZ-R-BRIX® release heat, keeping perishables from freezing. They will also protect from warming. Keeps perishables requiring a temperature range of 32° F to 60° F at a safe, uniform cool temperature for several days. Suggested quantity to use is equal ounces of bricks for the food to keep it cool or at least twice the weight of the food to keep it frozen. It is important to note that this product must be used in conjunction with an insulated container, such as EPS foam inserts or insulated mailers. See video on category page. STOCK ITEM. USUALLY SHIPS SAME DAY.