Unique comfort and side of support; Responsive, soft, supportive, performance-focused design; GuideRail technology provides gentle medial guidance for natural foot placement; Classic Altra EGO MAX midsole foam delivers light and luxurious performance; Updated heel shape; Elevated tongue details; Breathable mesh upper for improved fit and soft step-in; Altra Fit provides plenty of room for toe freedom; Secure midfoot support; Zero drop for natural movement