This Zojirushi Stainless Steel Mug Bottle Seal Packing Bottle Stopper Packing Water Stopper is made of durable stainless steel, making it perfect for storing and preserving your favorite beverages. The stopper keeps your liquids airtight and leak-proof, while the compact design is easy to store and transport. Enjoy your drinks on-the-go or at home with this seal packing bottle stopper.