New Balance Men's MK706 Non-Steel Toe Service Shoe Leather Synthetic sole Leather upper for natural comfort, durability, and breathability ROLLBAR TPU posting system minimizes rear-foot movement that, when combined with TS2 system, achieves the ultimate in motion control Polyurethane midsole provides lightweight cushioning and resists compression set Polyurethane outsole provides lightweight durability US Postal-approved shoe