Seamless, one-piece 3D stretch rebound stretch Chevron TechLoom upper provides a comfortable, custom fit. The TechLoom Chelsea features a newly developed, lightweight Propelium® midsole and traction pattern. The durable Propelium® rubber outsole with forefoot crash pad is designed to maximize energy generation and provide superior comfort that will maintain midsole structural integrity longer than conventional EVA. Newly developed lightweight Propelium midsole and new traction pattern. Durable rubber. The 8mm drop from the heel to the forefoot places your foot in a natural position.