Engineered mesh upper: A lightweight, breathable mesh material that reduces the need for additional overlays. Knit heel pull tab: This comfortable heel tab makes the shoe easier and more comfortable to put on and take off. 4D GUIDANCE SYSTEM feature: A dynamic pod designed to intuitively respond under excessive load. This response provides stability and comfort for the duration of a run. 3D SPACE CONSTRUCTION feature: Allows runners to improve compression at footstrike while catering to the gait differences between runners. It helps runners engage better with the foam while providing a softer feel underfoot. Rearfoot PureGEL technology: Softer, updated version of our GEL technology. Approximately 65% softer vs standard GEL technology.