Freshness and safety go hand in hand. If not kept at the right temperature, food and beverages can spoil, causing potentially dangerous bacteria to form. Foogo Phases stainless steel products feature Thermax double wall vacuum insulation which has been shown to inhibit the growth of bacteria in a laboratory test performed by Cornell University, and will keep beverages cold and fresh for ten hours. In addition to providing added protection from spoilage and food borne illnesses, Thermos also offers parents extra peace of mind in knowing that Foogo products use all FDA approved materials and do not use plastics containing bisphenol- A (BPA). Foogo Phases drinkware features interchangeable parts that fit all other phases cups. With interchangeable lids and handles, Foogo Phases drinkware easily adapts to a child's changing needs. To clean, hand wash or top rack dishwasher safe.