This beautiful cup is made of solid copper and the inside is finished with tin plating. Tin is known for bringing out the taste of sake due to high ion effect. And copper has a very high thermal conductivity and when you drink a cold drink in the summer you can enjoy the coolness in addition to the taste.The name of RED & WHITE was named from the comparison between copper red and tin white. RED & WHITE is called KO(= red/q) HAKU(=white/ ) in Japanese. It is regarded as a particularly special combination of colors in Japanese culture.