Very light and quick-drying ArmourDry technology improves performance. It disperses moisture evenly, allowing sweat to evaporate faster for a lighter, drier, cooler run. Energy Return cushioning for added protection in high-impact areas without bulk. The Locked-in Fit construction keeps the sock securely on the heel, so it doesn't need to be adjusted and won't fall off. The seamless toe provides excellent comfort and reduces irritation. The anti-odor technology reduces odor in the sock. Specific cut and design for left/right side.