Double Walled Stainless Steel Metal Mug (300Ml). the Outer Wall is Stainless Steel Metal, the Inner Wall is Plastic. the Screw-On Lid is Leakproof & has a Snap Opening. the Bottom of the Cup is Non Slip. the Double Walled Design Keeps Drink Hot or Cold for Several Hours & Prevents Condensation on the Outside of the Cup. Not Dishwasher Safe. Minimum Quantities Apply.