What's New: Updated Altra EGO(TM) MAX compound in midsole for a cushioned ride Re-designed engineered mesh upper for comfort, fit, and breathability GuideRail(TM) technology for medial support, only when it's needed Design: Standard FootShape(TM) fit Ghillie lacing system for a secure, customizable fit GuideRail(TM) technology adds support in key areas In-Shoe Comfort: Altra EGO(TM) MAX midsole provides lasting cushioning Additional Details: Weight (Size 8.5): 8.6 oz / 243.8 g