The Hydroflask 16 Oz Wide Mouth/Hydroflip Lid is made of long lasting and efficient components. It is double wall vacuum insulated. The effective water container keeps you hydrated anywhere you go. The bottle keeps cold up to 24 hours and hot up to 6 hours. It is the ideal combination of strength and flexibility. It is made of 18/8 Pro Grade Stainless Steel and is BPA-Free.