This size does not have a hole in the bottom, so you can also use it without a glass jar inside.<p>We designed the sleeve to fit tight enough that it won't fall off, but loose enough that it is still easy to get on and off. </p><p>Different brands of jars will vary a little in size, but it should stretch to fit almost any of them. </p><p>Use a different color for each family member, and stop wondering which jar is yours! </p><p> Microwave safe means you can heat up your beverage without removing the sleeve. Or take out a frozen jar of food, put a sleeve on it, and heat it up. </p><p>Since they don’t touch your beverage, I often just rinse them, but they are also dishwasher safe. You can leave them on the jar, but I find that water gets trapped so I prefer to separate them to clean the jar. </p><p>You could also use one to block sunlight or prying eyes from the contents of your jar. </p><p>Great for kids and adults!</p>