Made of 18/8 Stainless Steel, this series of coffee mugs are vacuum double insulated,which brings 3+ hours heat preservation for hot drinks and 9+ hours for cold drinks. The BPA-FREE lid for this coffee tumbler can be detached easily while providing 100% leak proof.Besides, we provide stainless steel straw for you. Powder coated, this insulated travel mug is sweat-free to grip.The classic no-handle design provides you with original experience of drinking coffee or tea. 18/8 stainless steel coffee mug is suitable for both hand wash and dish-washer.