The GT-2000 4 is the core runner's bread and butter with its balance of cushioning and stability. The updated Heel Clutching System delivers optimum support and the Impact Guidance System promotes a more natural gait. Continuing the tradition of comfort and stability, the Guidance Line and Guidance Trusstic System complement the comfortably supportive GEL Cushioning System, assisting mild to moderate overpronators alike with great support. The Dynamic DuoMax Support System adds an additional layer of FluidRide midsole foam on top of the support wedge to allow for a smoother transition and a lighter overall shoe. The ultimate run just got better with the GT-2000 4. Features : Upper features fewer material overlays for less rubbing on the foot and give for flexible expansion. FluidRide midsole technology provides the ultimate combination of bounce back and cushioning properties with reduced weight and exceptional durability. Rear and Forefoot GEL Cushioning Systems attenuate shock during impact and toe-off phases and allow movement in multiple planes as the foot transitions through the gait cycle. Impact Guidance System (I.G.S.) is ASICS' design philosophy that employs linked componentry to complement the foot's natural gait from heel strike to toe-off. Removable ComforDry insole provides cushioning performance and antimicrobial properties for a cooler, drier ride. Discrete Eyelets disburse lace tension to create a customized fit and enhanced upper comfort. Exoskeletal Heel Clutching System heel counter provides improved support and creates enhanced heel-fitting environment. DuoMax Support System dual-density midsole is positioned to enhance support and stability DuoMax reduces weight and increases platform support. DuraSponge outsole is comprised of blown AHAR rubber compound for increased cushioning and durability in the forefoot. AHAR stands for ASICS High Abrasion Rubber. It is used in critical areas of the outsole for increased longevity. Vertical flex groove, the Guidance Line, decouples the tooling along the line of progression for enhanced gait efficiency. Guidance Trusstic System integrates Guidance Line construction for enhanced gait efficiency while providing midfoot structural integrity. American Podiatric Medical Association (APMA) seal of acceptance.