PREMIUM MATERIAL: At HOMISBES, we always choose materials carefully in order to create high qualified and durable products which are safe for users’ health. The cup body is made from 18/8 food grade stainless steel, so this tumbler is durable, unbreakable, rust-resistant, and doesn’t transfer the flavor of your beverages. The BPA-free clear lid that seals the cup tightly keeps spills under control and allows you to see inside.