These silicone sleeves for Half Gallon (64oz) Mason jars add grip and padding, and they also insulate. We have tested current production Ball and Kerr jars, but they can’t fit all vintage jars. Whether you call it a Koozie, a Kozie, a Coozy, a Cozy, or just an insulating sleeve, it’s perfect for protecting your glass jar from breakage and your hand from cold or heat. They are perfect for pitchers for 1/2 Gallons of milk, juices, lemonade, iced tea & iced coffee. Made of silicone rubber, these sleeves are dishwasher, freezer, and microwave safe! Silicone is a safe, green, non-plastic (BPA free) material for food use that does not leach any chemicals. Great paired with our pour and store lid with handle!