NIKE Air Zoom Structure Triax+ 15 Running Shoes Lightweight breathable open sandwich mesh upper - keeps your feet cool whilst our running Phylon midsole - A responsive, cushioned EVA midsole material keeping you from landing too Dual density - Higher density EVA on the medial (inside) of the shoe which helps prevent o Dynamic Archbridge - TPU (plastic) bridge that sits next to the dual density and acts as a TPU overlays - Supportive overlays lock your foot in place and stops it from slipping abou