FREE YOUR FEET AND EMBRACE THE TRAIL WITH THE PUREGRIT®. Working with Ultra-marathon runner Scott Jurek, Brooks have developed a unique one-piece outsole that has a concave shape. When forces are applied, the piece splays out to provide a more balanced lay-down. A sleek grip lug pattern and wide base protect the feet but still allow the runner to get in touch with the ground. Brooks have topped it off with an ultralight mesh and conforming foam upper for a fit that really hugs your foot