New Balance Men's MR8512 Running Shoe 100% Synthetic and mesh NB ZIP is strategically located struts engineered between top and bottom plates, formulated for optimal cushioning, responsiveness and durability ABZORB provides a superior blend of cushioning and compression set features with Dupont Engage and Isoprene rubber for the ultimate ride ACTEVA is 12% lighter than standard midsole foam with DuPont Engage for exceptional durability Ndurance is a rubber compound for maximum durability used in high wear areas