HIGH-QUALITY MATERIALS: Our baby bottle caps are crafted from high-quality materials, guaranteeing durability and preventing leaks. Rest assured, your baby's milk or formula stays fresh and safe. AIR TRAVEL FRIENDLY: Ideal for air travel to counteract cabin pressure effects. EASY TO MAINTAIN: Reusable baby bottle travel caps are dishwasher-safe (top rack), suitable for electric sterilizers, microwave sterilizers, or boiling water. BPA-free for safety. LEAK-RESISTANT DESIGN: Seal rings ensure excellent sealing ability , preventing leaks even during prolonged inversion and strong shaking. VERSATILE USAGE: Perfect for storing bottles in the fridge and convenient for commuting or traveling.