Meets afi 36-2903 (air force) requirements for optional wear Durable, rough-out leather upper with lightweight 1000 Denier nylon and breathable, moisture-wicking mesh Lining for hot weather Semi-locking side-zip Danner tanicus slip-resistant outsole with pentagonal lug pattern offers superior durability and stability Non-metallic toe meets or exceeds ASTM F2413-11 I/75 C/75 EH