The ball of the foot pad evenly distributes body weight due to pressure and friction calluses ( hardened skin) may form. Calluses can cause discomfort when walking such as a burning sensation under the foot or a feeling of walking on stones. Epitact Plantur Cushions eliminate calluses and cushion the ball of the foot to help relieve pain. . Relieve ball of the foot pain. Thin and comfortable pads. Can be worn in all types of shoe. Small UK size 4-5.5 EU 36-38 Reusable and machine washable.