RB4248 ASTM F2413, Composite Toe, XTR® Brand Composite Toe Cap, Static Dissipative (SD 10) with Dual Resistor, Slip Resistant, Metal Free,100% Non-Metallic, Static Dissipative (SD 10) with Dual Resistor, The Print Work ULTK has a dense outer rim midsole for support and central rubber lugs for traction. The Ultraknit upper is irritation-free for all-day comfort with an athletic look. The composite toe provides impact protection that meets or exceeds ASTM F2413-17 safety standards.