Spiro ST S3 | BlackThe Spiro ST S3 is built with all the features you would expect from a Cat work boot. It incorporates ERGO, a series of design principles that work together to provide footwear that promotes foot health by integrating stability, flexibility, and comfort. Conforms to EN ISO20345: 2011 Safety Footwear Standards Strobel and Cement construction Removable Nylex and PU insole T870 rubber outsole Penetration resistant poured PU midsole Impact and compression