ASICS Men's Gel-Nimbus 18 Lite-Show Running Shoe 100% Synthetic Imported Rubber sole Shaft measures approximately 3.5" from arch mpact Guidance System (I.G.S) (Running) : ASICS design philosophy that employs linked componentry to enhance the foot's natural gait from heel strike to toe-off. Reflectivity FluidFit: ASICS FluidFit upper technology combines multi-directional stretch mesh with stretch reinforcements that adapt to the athlete's foot, creating a truly customized glove-like fit. FluidRide: FluidRide provides the ultimate combination of bounce back and cushioning properties with reduced weight and exceptional durability. Rearfoot and Forefoot GEL Cushioning Systems: Attenuates shock during impact and toe-off phases, and allows movement on multiple planes as the foot transitions through the gait cycle.