Asics GEL-Nimbus 13 Running Shoes has dropped ¾ of an ounce, thanks to the new super light, super durable AHAR outsole material. Full length Guidance Line gives the shoe a smooth transition through the gait cycle, and promotes a more efficient toe-off position. Impact Guidance System - ASICS Design Philosophy. Employs linked componentry that enhances the foot's natural gait from heel strike to toe-off. Guidance Line - Vertical flex groove decouples the tooling along the line of progression for enhanced gait efficiency. Gender Specific Forefoot Cushioning - A top layer of injected Solyte provides a cushioned platform feel in the forefoot. Women's models feature a lower density for improved cushioning and forefoot comfort. Gender Specific Space Trusstic System - Recognizes the normal periodic changes in the shape of the woman's arch and provides for the controlled deformation of the arch into the space within the system. ComforDry Sockliner - Provides cushioning performance and anti-odor properties for a cooler, drier, healthier environment. Biomorphic Fit Upper - Stretch material strategically placed on the upper helps to reduce buckling and the potential for irritation. Asymmetrical Lacing Design - An anatomically correct lacing environment that reduces potential for irritation and provides improved comfort and fit. Discrete Eyelets - Independently placed eyelets disburse lace tension, creating a customized fitting environment and enhanced upper comfort.