The Saucony Endorphin Pro 4 running shoe is snappy and responsive yet smooth and efficient. This is achieved by fusing PWRRUN PB and PWRRUN HG together in the midsole – an industry first. A full carbon plate adds longitudinal stiffness and maximum metabolic efficiency. And the silky-smooth heel liner and integrated tongue system makes this marathon shoe feel like slipping on an old friend come race day. The unique carbon plate is engineered for longitudinal stiffness and maximum metabolic efficiency and around the foot is their silky smooth heel liner and integrated tongue for a connected comfort.