This 10 Oz stainless steel cup is made of food-grade 304 stainless steel which contributes to the unbreakable characteristics of the mug. The cups are great for wine/beer/coffee/milk/ ice water, etc. And they are rust-resistant.It is is a very cool design. The ergonomic design of the mug makes it very easy for the kids to hold. Meanwhile, the bottom is smooth but anti-slip. The stainless steel tumbler is very light; you won’t feel any extra hurdle when holding it.The mugs are stackable and they are very easy to store and portable. And the cups are very easy to clean after drinking. They are dishwasher safe.The cups are environmental-friendly and completely recyclable. Very suitable for or BBQ/Home/Office/Party/Driving/Camping.