Proton Exchange Membrane or PEM Fuel Cells are considered to be the most versatile type of fuel cells currently in production. They produce the most power for a given weight or volume of fuel cell. Because they are lightweight, have such high power-density, and cold-start capability, they qualify for many applications, such as stationary combined-heat-power, transport, portable power and even applications in space. The stack provider of choice for integrators who aim at project based high-power applications and whom subscribe to high lifetime and efficiency requirements.