Just like the brooks core line the pureproject series is held to the industry highest wear test and durability standards because of their lightweight construction and fewer materials runners should generally expect shoes from the pureproject line to last approximately 250 300 miles the lightweight construction and lush cushioning of the pureflow 4 are a perfect match for each other the nav band is a flexible band that wraps over the instep to comfortably secure the foot in place the dynami