Acrylic Outer And Inner. Double Wall Construction For Insulation Of Hot Or Cold Liquids. Insert Decoration Is Inserted Between The Clear Double Walls Of The Tumbler Then Ultrasonically Sealed To Provide Double Wall Insulation. Snap-On, Spill-Resistant Thumb-Slide Lid With Rubber Gasket. Lids Packed Separately And Unassembled. Meets FDA Requirements. BPA Free. Hand Wash Recommended.