Description For aspiring track athletes, the New Balance FuelCell MD500 V9 is a sleek, lightweight track spike great for middle to long distance races. The MD500 is equipped with a full-length FuelCell midsole that offers a propulsive feel perfect for racers striving to go faster. A 6-pin TPU spike plate with removable spikes provides an aggressive but forgiving ride perfect for a wide range of track events.