New Balance Fuelcell MD500v9 Running Spikes 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. Synthetic and Mesh Upper Designed to provide lightweight comfort on race day, the New Balance MD500v9 Running Spikes have been constructed using a synthetic and mesh upper. The lightweight mesh allows cool air to flow throughout the upper whilst, at the same time allowing hot humid air to escape; this creates a perfect microclimate for your skin to thrive in. The increase in airflow allows you to remain cool, dry and comfortable at all times. To ensure a reliable and secure fit, the upper features a traditional tongue and a collar construction for maximum comfort. The tongue sits comfortably against the skin and reduces the risk of chafing and irritation so you c