synthetic-and-rubber Foam sole Rearfoot and Forefoot GEL Technology Cushioning System - Attenuates shock during impact and toe-off phases, and allows movement in multiple planes as the foot transitions through the gait cycle. Engineered monofilament upper - FlyteFoam Propel Technology - ASICS energetic foam formulation that provides supreme bounce thanks to a unique elastomer compound. EVA Sockliner - Removable sockliner that provides cushioning performance. AHAR Outsole - Acronym for ASICS High Abrasion Rubber. Placed in critical areas of the outsole for exceptional durability.