The Smartwool Women's Run Zero Cushion Low Ankle Socks are engineered for female runners who demand a minimalist, ultra-responsive feel. Designed with a women-specific anatomical fit that features a narrower heel and slimmer profile, these ultralight socks eliminate bunching and slipping in low-volume running shoes. Combining the unmatched breathability of ZQ-certified merino wool with a protective Achilles tab and a zero-cushion design, they deliver optimal temperature regulation and blister-free performance on your fastest, hottest runs.

Specs & Features

​Technical Specs

• ​Model Number: SW001668
• Height: Low Ankle (Sits just below the ankle bone with an extended Achilles heel tab)
• ​Cushioning: Zero Cushion (The absolute minimal thickness for high breathability and immediate ground feedback)
• ​Material Composition: ~46% ZQ-certified Merino Wool, 49% Nylon/Recycled Nylon, 4% Elastane, 1% Polyester

​Key Features

• ​Women's Specific Fit: Anatomically engineered with a narrower heel cup and a generally slimmer profile to perfectly contour to the female foot, completely eliminating loose fabric and heel slip.
• ​4 Degree™ Elite Fit System: A performance-oriented, multi-zone elastic band system that securely hugs the arch and instep for a locked-in, supportive feel.
• ​Indestructawool™ Technology: Advanced knitting techniques that reinforce the entire sole, ensuring this ultralight sock can withstand high-mileage training.
• ​Shred Shield™ Technology: Greatly reduces wear from toenails, extending the lifespan of the toe box.
• ​Virtually Seamless™ Toe: Eliminates the bulky internal seam at the front of the foot to prevent chafing and blisters.
• ​Integrated Achilles Tab: A raised cushion at the back of the heel prevents the shoe collar from rubbing and keeps the sock anchored in place.

​Care Instructions

​To preserve the precise women's fit and premium merino fibers, follow these guidelines:

• ​Wash: Machine wash warm or cold on a gentle cycle. Wash inside out to flush away dead skin cells, sweat salts, and trail dust. Wash with similar colors.
• ​Detergent: Use a mild liquid detergent. Never use fabric softeners or bleach, which coat the merino fibers and destroy their natural moisture-wicking and odor-resistant capabilities.
• ​Drying: Tumble dry on low heat, or line dry in the shade to protect the precise elasticity of the 4 Degree™ Elite Fit system.
• ​Ironing/Dry Cleaning: Do not iron. Do not dry clean.

​X-Boundaries Professional Tips

• ​The Perfect Pairing for Racing Flats: Because these feature "Zero Cushion," they are the ideal choice for snug racing shoes, carbon-plated supershoes, or tight track spikes. They provide the blister protection and sweat management you need without taking up any extra volume inside the shoe.
• ​Say Goodbye to Heel Slip: The combination of the women-specific narrower heel cup, the 4 Degree™ Elite elastics, and the protective Achilles tab makes this sock nearly impossible to pull down into your shoe while running.
• ​Summer Heat Essential: Ultralight merino wool excels in scorching summer temperatures. It actively pulls moisture vapor away from your skin before it turns to liquid sweat, keeping your feet noticeably cooler and drier than standard synthetic running socks.