Seeking long distance relationships. Everyone needs a “ride or die” partner. One who will always be there, win or lose. That's the Endorphin Pro 4. Snappy and responsive from the get-go, yet smooth and efficient by nature. The combo is set on top of a full carbon plate engineered for longitudinal stiffness and maximum metabolic efficiency. And when you add Speedroll technology, proven to help you propel in a forward-rolling motion, a silky-smooth heel liner and integrated tongue system, you'll feel like you're slipping on an old friend come race day.