Brooks Women's Launch Running Shoes 100% Synthetic Rubber sole Rear and Forefoot Hydroflow Cushioning - the contained silicone-oil compound dampens the i DRB Accel - this plastic shank like device provides torsional rigidity to the midfoot, whi S-257 Cushsole - an energy efficient midsole compound which is used as an insole to offer HPR Plus Outsole - a highly durable rubber compound to reduce wear and increase the life o Contact Rubber Forefoot - adds extra grip to the sole