Merino Wool and Bombas Performance Running: A match made in workout heaven. Merino Wool is already a naturally soft, breathable, moisture-wicking, and quick-drying yarn. But we blended it with polyester and spandex to create a design that offers more stretch for an arch support system and a contoured fit for your foot. It’s this combo, and all the other innovations of our Hex Tec socks, that makes these pairs an all-workout-ready force to be reckoned with.