Sygnius Stainless Steel Tumbler with Transparent Plastic Lid fixed with a silicon gasket. Stainless steel is lauded for its durability and is also one of the safest materials used in the kitchen.These tumbler is therefore safe, sturdy and efficient at storing your beverages for longer periods of time.These tumblers are perfect for carrying liquids like mineral water, juice, coconut water, tea, coffee,butter milk and cold drinks while travelling. As these tumblers are airtight, they do not allow the liquid contents to seep out and ruin other items in your bag.The wide mouth design allows you to clean them efficiently to maintain hygiene.