ack Curtin Edition. 4 Way Stretch Collar Sock-like fit provides a comfortable, secure fit. One-piece Toe Embossed toe line with no seams to rip. Full-length CCAP midsole. Classic, lightweight moulded EVA improves shock absorption and general comfort. Twin Rubber Cupsole Retro styling with modern performance and comfort Improved tread pattern. Staggered depths of treads to improve the grip from the original.