The inner wall of the tea infuser bottle is made of 304 grade stainless steel, also have silicone bottoms, designed to keep from slipping and spilling, no worry about the oxidation and corrosion, and won’t leave a metallic taste or rust easily, avoiding changing the taste of drinks (such as tea, coffee, and juice), which are safe and healthy to use. Insulated mug is perfectly suitable for daily use, running, hiking, camping, etc.