Mason and Canning Jar uCap Purple Silicone Storage Cap for Standard or Wide Mouth, 4" Diameter (2, Wide) Free shipping on orders over $50! The Blossom Storage uCap turns Standard or Wide mouth Mason, or other canning jars into an airtight and liquid tight container. Made from food grade BPA free silicone. Dishwasher, microwave, and freezer safe. All uCaps come individually packaged on a stylish card. (Ex. 6 packs have 6 caps attached to 6 separate cards.) This makes them perfect for gifts! Perfect for storing food in bulk in pantries or freezers. Pack easy to transport lunches for an entire week!