This is likely an Osaka Suzuki sake cup made of tin. Genuine tin. Size: (approx.) 7.5 x 8 cm I have a similar genuine tin beer glass, and since I don't use this one, I'd like to sell it. I've used several items made of bendable tin, but they tend to deteriorate due to metal fatigue and become distorted with use, making them look bumpy. Therefore, I recommend this one, which is more durable for long-term use. According to the website, the products are made of 90% or more tin. It comes with the instruction manual and box. Thank you.