ASICS Men's GEL-Fortitude 4 Running Shoe 100% Mesh and synthetic Rubber sole The Rearfoot Gel Cushioning System attenuates shock during impact phase and allows for a smooth transition to midstance Comfordry sockliner provides cushioning performance and anti-microbial properties for a cooler, drier, healthier environment P.H.F. (Personal Heel Fit) lines the collar and mold to the athletes heel, creating a personalized fit SpEVA Midsole Material improves bounce back characteristics and decreases midsole breakdown Trusstic System reduces the weight of the sole unit while retaining the structural integrity of the shoe