The Sorbo pad forms a transverse arch and cushions the impact on the arch of the foot. Infrared yarn is used in the main fabric. This is a comfortable material with excellent heat retention. Sizes: S: 22.0-24.5cm, L: 25.0-27.5cm Individual packaging size: 18 x 11 x 3 cm Individual packaging weight: 75g Materials: Body: Polyester, nylon, cotton, polyurethane; Pad (Sorbo): Polyurethane I have two pairs for replacement! One pair is 1800 yen. Thank you. S size is also available!