Transform your mason jars into cute, unique jelly/jam jars! These lids are BPA free and made from recycled materials, especially designed to bring even more uses to your regular mouth mason jars (jar not included). We recommend using a 4, 8, 16 or 32 oz. jar for best use. To use, apply some force to snap lid on. This set includes four lids, making it easy to label your preserves. Cover, fill, decorate! Because, let's be honest, everything's better in a mason jar.