Stainless Steel. Double walled vacuum insulation for temperature retention. Two-way use lid: sipper hole and straw (straw not included). Lid has a drinking spout and optional straw insert plug. Screw-on PP Plastic lid with snap closure. Leak resistant lid. Black Silicone bottom band. Non slip bottom base. For use with hot and cold beverages. Holds up to 450 ml. (15 oz.). Individually retail packaged. BPA free and FDA compliant.