Recommended by doctors and pedorthists world wide, The New Balance Orthotics NB 400 insole is tri-density with a molded Pedic core to support the arch and provide maximum comfort. Top cover features X-Static, a fiber made with pure silver for an improved antimicrobial, anti-odor and thermodynamic natural performance. Antimicrobial Cupped rearfoot for cushioning and stabilization Recommended for medium and high arch feet, and a neutral forefoot without metatarsal support for those not suffering from ball-of-foot discomfort Anti-Odor Anti-Static Thermodynamic 100% Natural Style # NB400