Try the new version of infinite energy. Super elastic DNA AMP cushioning plus a softer and more flexible Knit Fit upper for total comfort. Brooks's most reactive midsole, DNA AMP, does more than amortize. Control, capture and return the energy to help you fuel your run. Your energy reserves are not unlimited. Then the Brooks engineers intervened to create a flexible arrow-shaped motif on the outer sole to make movement from the heel to the fingers faster, without losing energy. Comfort passes in invisible mode inside the elegant upper fit in Fit Knit. Hidden features include a heel wrap and an ultra soft heel tab to protect your Achilles heel from irritation.*From the manufacturer's description