Apply To JAR FIT: Compatible with Ball and Kerr and other jars while using unlined plastic jar lids from Ball and other , also fits metal lids. SAFE: Food grade silicone, dishwasher safe, freezer safe, heat tolerant, reusable. MULTI-USE: Great for everyday storage, / lunch and travel, storage of dehydrated food and much more. WIDE MOUTH SIZE: Fits plastic wide mouth jar lids providing an airtight leakproof seal fits 86mm lids). Keep in liquids, keep out bugs and moisture. All the things you need for an airtight seal are provided by these silicone rings. They also are compatible with major like Ball and Kerr. In addition, if you have metal lids, these provide a sturdy liner.