Now with 20% more bouncy underfoot cushioning and 15% less weight against the ground, you'll feel even faster and more comfortable with every step wearing ASICS GEL-Cumulus 17 running shoes. The addition of the FluidFit® system in the upper will hug and move with your feet to create a much more seamless and enjoyable experience. New colors bring out the fun in every run.Upper: FluidFit® combines engineered mesh and seamless overlaysthat stretch, hug and move with the foot. Padded tongue and heel collar enhance comfort. Lace-up front offers an adjustable fit.Midsole: FluidRide™combines cushioning and lightweight responsiveness. Impact Guide System (I.G.S.®) employs linked componentry to enhance the foot's natural gait from heel strike to toe-off. ComforDry™ X-40 sockliner provides cushioning performance and plush luxury with antimicrobial properties for a cooler, drier and healthier environment. Rearfoot 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. Removable insole.Outsole: Guidance Line® vertical flex groove decouples the tooling along the line of progression for enhanced gait efficiency. AHAR® ASICS High Abrasion Rubber placed in critical areas provides exceptional durability.