Design: The 4D GUIDANCE SYSTEM(TM) guides the foot through every step with adaptive, on-demand stabilty New knit collar construction and pull-tab offer a modern step-in with easy on and off access Engineered mesh upper helps keep you cool and comfortable during long-distance runs Designed for neutral/overpronation Reflective details designed to improve visibility In-Shoe Comfort: PureGEL(TM) technology helps deliver enhanced shock absorption and even smoother transitions FF BLAST(TM) PLUS ECO foam provides soft cushioning, made from approximately 20% bio-based content using renewable resources OrthoLite(TM) X-55 sockliner improves comfort Durability & Traction: The HYBRID ASICSGRIP(TM) outsole provides better grip and more softness underfoot Additional Details: Approximate Weight (US men's size 9): 305g/10.7oz Heel Height: 40mm Forefoot Height: 30mm The new GEL-KAYANO(R) 31's carbon footprint is 27% lower than the industry average Sockliner is produced with the solution dyeing process that reduces water usage by approximately 33% and carbon emissions by approximately 45% compared to the conventional dyeing technology