This is not just another plastic Sippy Cup. This is the one of a kind, Superb Sippy Cup with a Flexible, Bendable, Reusable Silicone Straw! The inner body straw is made of robust Tritan™ to ensure it performs continuously and effectively day after day! The 16 oz./ 450 ML capacity stays cold for up to 24 hours because it is made of copper lined, double wall Vacuum insulated 18/8 stainless steel.