The SMART Stainless Steel 1.75 cup (13.5 oz.) Thermos has rubber sealed lid and vacuum liner to provide good insulation. Lid can be open at 180 degree making it easier to fill up and clean. Material. Stainless Steel 18-10. Features Elegantly Durable -- Designed from heavy gauged polished stainless. Stainless Steel -- Resistant to scratches or other surface damage. -- Withstands high levels of heat without damage. -- Resistant to rust, corrosions and interactions with acidic foods. -- Food safe and easy to clean. Stainless Steel construction -- Provides durability and strength.