Turn any regular-mouth Mason jar into an airtight storage container with Tough Tops. Unlike other plastic storage lids that bend and buckle, Tough Tops are built to last. The underside of each lid has a custom gasket channel that holds the BPA-free gasket in place at all times - no more wondering if a tight seal has actually been made or struggling to keep your gasket secure. Tough Tops are perfect for liquid and dry storage, as well as crafts, hardware, sewing supplies and much more! When it's time to clean, just pop them in the dishwasher. They won't warp or crack and will protect the contents of your jars for years to come.