It is made of Stainless Steel. The vacuum cup is characterized by exterior automotive paint process, stainless steel and electrolytic grinding layer and high vacuum insulation layer and inner container ultra-microwave copper plating layer and inner container 304 stainless steel layer. so that it can keep hot water for 6hours and cold water for 10hours. Make an essential addition to your morning commute with this 17 oz. Customized Logo and Color Available. Pricing include shipping cost to ca. QTY over 1K pcs by sea. 100% guarantee for quality. Rush service is available. Thanks for your inquiry.