Designed to be Warm, provide Insulation, Comfort and Support, the SIDAS 3 Feet Merino insoles offers optimal thermoregulation and reduces undesirable odor. Highly resistant and durable, the 3 anatomical shapes are specifically tuned for Low, Medium and High arches. 3 Feet (R) = Three shapes fit all. Sidas 3Feet Winter Merino Mid Insoles | Medium | Christy Sports