Women's MBTA(R) Colorado X :: The MBTA(R) Colorado X is an athletic walking shoe built to increase your active lifestyle and aid in recovery. The Colorado athletic walking shoes feature a synthetic leather/mesh upper finished with a mesh footbed our signature rocker sole and non-marking rubber outsole. Accepted by the American Podiatric Medical Association for promoting quality foot health. The Colorado X athletic shoes are at the Performance level of the MBTA(R) Index which generates an increased level of rock due to its strong sole curve and Pivot Axis for increased activation. The Responsive running profile is for the runner who wants additional cushioning but also a responsive feel.