Thorlo XCCU Experia Multi-Activity Socks has a lightweight Achilles Tendon pad that protects against rubbing and chafing while functioning as a heel lock. THOR WICK COOL fiber in the ball and heel pads provides enhanced moisture management. Specially sculpted THORLO pads in the ball and heel provide protection from shear and impact where needed. All but most of the essential padding, significantly reducing the weight of the sock. Ultra lightweight sock frame. Nylon covered LYCRA provides contoured aerodynamic glove-like fit. Mesh Polyester for maximum breathability. High performance runners, cyclists, hikers and fitness walkers who prefer a minimal amount of foot protection. Care Instructions: For longer product life, maximum protection and comfort, wash and dry inside out to fluff up the pads using liquid fabric softener after each use to lubricate the fibers for longer life. For optimal benefits, liquid fabric softeners are always recommended. Do Not Bleach. Wash Normal: 105F/40C. Dry Normal in medium temperature. Do Not Dry Clean. Do Not Iron.