It is made of stainless steel. Double wall stainless steel will keep ice from melting completely over night. It is perfect for the gym and for other sporting activities. Also it works great for hiking, camping and outdoor activities. It can be used as a water bottle or a thermos and is extremely versatile. Company logo and name can be imprinted. 18 oz, 28 oz, 38 oz, 50 oz are also available. Price below is for 28 oz.