The Reebok CrossFit Nano training shoe features a synthetic and mesh upper that provides breathability and protection. Visible U-Form Custom Fit Technology offers excellent fit. DuraGrip toe cap application delivers enhanced abrasion resistance. Full-length, low profile IMEVA midsole with a 9mm heel to 5mm toe drop adds a natural fit and feel. Removable Ortholite foam sockliner is suitable for orthotics. High abrasion carbon rubber outsole and sidewall lug wraps give durability. Wt. 9.3 oz. U-Form Instructions: 1. Place hairdryer inside shoe and blow hot air for four minutes (DO NOT USE OVEN). U-Form tab will turn red. 2. Remove hairdryer from shoes 3. Lace up shoes as you normally would and wear them seated for eight minutes (U-Form tab will return to black color) 4. Your shoes are ready to go!