The Isolator Fitness ISOBricks are designed to remain flat regardless of how you freeze or store them to leave more room for your food containers and other essentials within your ISOBag. The unique manufacturing materials of the ISOBrick ensure that your food stays cold while you workout, travel or even explore the great outdoors. This ISOBrick pack comes with 2 of our 12 oz ISOBricks that fit perfectly within your ISOBag to keep your meals fresh and cold for up to 12 hours.