The Spiro is built with all of the features you would expect from a Cat work boot and then some. Featuring ERGO; a series of design principles that work together to deliver footwear that promotes foot health by integrating stability, flexibility and comfort - enhancing the natural movements of the foot. ASTM F2413-11 I/75 C/75 Steel Toe. Full grain leather upper. Nylon mesh lining. Nylex + PU sock liner. Poured PU midsole. Ultra work compound outsole. Cement construction.