Synthetic-and-mesh Rubber sole FlyteFoam Propel Technology - ASICS energetic foam formulation that provides supreme bounce thanks to a unique elastomer compound. AHAR Outsole - Acronym for ASICS High Abrasion Rubber. Placed in critical areas of the outsole for exceptional durability. Reflectivity - Contains reflective materials designed to enhance visibility during low light hours. Heel Clutching System Technology - Exoskeletal heel counter provides improved support and creates improved heel fitting environment. Plus 3 Midsole Technology - 3mm of additional height on women's models helps relieve achilles tension.