Engineered to outpace the demands of urban running, this sock-fit shoe sports a ribbed lacing cage that locks your foot comfortably to the springy foam sole. Responsive Speedboard™ construction moves naturally with your stride to transform every heel strike into an explosive toe-off, with durable, high-abrasion rubber in the tread providing superior grip. The snowy-white silhouette is punctuated with stealthy pops of color inspired by the legendary story of Suma, the black panther who escaped the Zurich Zoo in winter of 1933. Cushioning: absorbs impact and distributes weight for consistent, buoyant comfort under each step Energy return: transforms every heel strike into responsive, explosive forward movement Pull-on sock upper with external lacing cage Speedboard construction moves naturally with your foot to transform every heel strike into an explosive toe-off Helion™ superfoam cushioning delivers lightweight energy return even in hot and cold temperatures Removable insole Textile and synthetic upper/textile lining/synthetic sole