Thorlos Original is made with clinically-tested padding that is uniquely designed and applied to provide maximum cushioning under the ball and heel of your foot for maximum impact and friction (anti-blister) protection and any other pressure/friction point created by your sport-specific activity. Thorlos Brand Promise Guarantee - Your feet will feel better or your money back! Made in the USA. Thorlos: Better feet. Better life. Thorlos clinically-tested padding under the ball and heel provides maximum protection from friction, the primary cause of blisters, and impact protection where needed most Constructed with THOR•LON fibers for superior softness, resilience, durability, and moisture-wicking for drier, better feeling feet Contoured ventilated sock frame for less weight, more breathability and an aerodynamic fit together mean your feet will stay cooler Flat knit instep and cushioning in arch for better fit, more support and less pressure on the feet for a more comfortable run Low profile toe seam won’t rub or irritate your foot