The size is suitable for those who wear 21-23 cm. See the second photo. The thong can be adjusted, so I think it will last a lifetime. Both the platform and the thong have a sheath-shaped design, and the platform appears to be cork. The back is genuine leather, so I think it's authentic. There are also adjustment holes, so you can fine-tune the thong and the front post to fit your feet. This is a real zori, not a casual one. I'm not sure if the part of the thong that touches the instep is synthetic leather or genuine leather, but it's made of leather, so it might feel a little stiff on your feet. Beginners of Japanese footwear should be aware that they need to get used to it with determination and practice (by gripping with their feet to prevent slipping and walking with a forward center of gravity). For how to wear them, please refer to YouTube's Maruya Channel, etc., which has detailed information. Those who are used to wearing them should be fine, but the thong is also thin, so if you don't grip it firmly, you might get blisters. A small bag for carrying valuables is also included. I received these new and unused, so I'd like to send them to someone who will use them.