Solid copper with nickle lining and solid brass accents. Other less expensive moscow mule mugs are typically made of stainless steel that has been copper plated. Of the mugs we sell, they are both great mugs. However, aficionados (us included) would also say the taste is better and the drink stays colder in a real copper mug vs a stainless mug that is copper plated. The cost difference is the difference in the cost of producing solid copper mugs vs stainless steel with copper plating. That being said, if you want a solid copper mug, made just like they were over a hundred years ago, then this is the mug for you! if you're a little more price conscious, be sure to look at our other moscow mule mugs made of stainless steel with copper plating. Handcrafted from genuine, quality copperrninside is nickel linedrnholds 16 oz; measures 4" tall and 3" in diameterrnhand wash only