stainless Product size (W x D x H): 3.3 x 3.3 x 3.9 inches (8.5 x 8.5 x 10 Capacity: 0.3L High heat retention and cold retention, "Stainless Steel Vacuum Double Layer Blower Construction" Resists condensation even with cold drinks and stays cool to the outside when filled with hot beverages Inner matte finish; Diameter: Approx. 3.0 inches (7.5 cm); Not dishwasher or dryer safe