Thermos 'Phases' Drinkware features interchangable parts that fit all 'Phases' cups. Phase 3 for children ages 18 months and older. Thermos double wall vacuum insulation for maximum cold temperature retention. Hygenic push button lid with pop-up silicone straw is easy to open Kid-proof design, durable stainless steel interior and exterior Contoured body is easy to grip Sweat-proof won't leave water rings Dishwasher safe. Keeps beverage cold for up to 10 hours.