S: (Men's US 6.5-8.5 24.5cm-26.5cm / Women's US 8.5-10.5 26.5cm-28.5cm) This is an insole. Uses polyurethane and air cushioning. Features a quick-drying microfiber liner. Offers outstanding durability. Please consider that it will raise the height by approximately 0.5cm. It also helps prevent deterioration inside the boots. Cushioning is also significantly improved, and it is recommended. Used briefly in boots once.