Design: Engineered mesh upper Rocker shape geometry encourages an efficient toe-off and a smooth, quick roll through your stride In-Shoe Comfort: Refined molded heel collar provides a comfortable, secure fit Roomy toe box and zero drop, built to keep you comfortable and keep you running Plush Ortholite X55 footbed provides an improved step-in feel that will follow you with every stride Softer Altra(R) EGO(TM) MAX midsole foam than the previous version for improved comfort Additional Details: Weight: 9.6 oz / 272g Stack Height: 33mm Drop: 0mm