Newly developed molded Lycra collar and tongue with sculpted heel to provide full range of motion. Non-stretch Techloom forefoot keeps your foot secure and stable throughout your workout. New lacing system limits lace-loosening during your workout to keep you performing your best. Phantom lace loop eyelet offers the option to tuck your laces for streamline look. New sockliner offers exceptional cushioning to handle even the most extreme training session. Propelium™ is designed to maximize energy generation and provide superior comfort that will maintain midsole structural integrity longer than conventional EVA. Lightweight Propelium midsole. Durable rubber outsole with forefoot crash pad. The 8mm drop from the heel to the forefoot places your foot in a natural position for efficient running