These silicone sleeves for Quart (32oz) Mason jars add grip and padding, and they also insulate. These fit both regular and wide mouth jars. 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. 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. Multi Purpose - Coffee, beer, soup, salad - whatever you're sipping or snacking, they're all tastier from Mason jar! Add a drinking lid, or stainless steel lid & straw, to make a plastic free travel mug. Or add a leak proof lid and bring lunch to work or store bulk snacks in easy to go portions in the pantry.