Stainless Steel Outer And Inner. Double Wall Construction For Insulation Of Hot Or Cold Liquids. Snap-On, Spill-Resistant Flip Top Lid with Straw Hole and Matching 9 1/2" Straw. Vacuum Insulated. Due To Vacuum Insulation Technology, Capacity Is 22 Oz. With Lid On. Non-Slip Bottom. Meets FDA Requirements. BPA Free. Hand Wash Recommended.