● Product size: One foot outer dimensions 25cm x 10cm x height 10cm ● Weight: Approximately 350g for both feet ● Material: Polyester ● Suitable size目安: 23~24.5cm The instep can be adjusted with Velcro, so I think you can use it without worrying about the size. ● The unevenness like a rock massages the soles of your feet. ● Stimulates acupressure points just by wearing and walking. ● You may feel pain at first, but it becomes pleasant as you get used to it?! And it's healthy!! I purchased it on Amazon in August 2024 and tried it indoors, but it was too painful for me and I couldn't use it. I hope someone can use it. Thank you.