Heading into a trail race? Bring an aid station with you—right on your back! Women's specific styling contours where it counts, so AA's and D+ cups alike can breathe deeply. Included dual 17oz soft flasks with bite valves keep hydration accessible. Pockets galore for all the fuel, layers, poles and GoPro action long mileage demands. 78% poly/22% spandex; 100% poly; poly foam. Sizing based on chest measurement. S(34-35½"), M(35½-37½"), L(37½-40").