Note 1 to entry: External manifold design refers to a fuel cell stack where the gas mixtures are supplied from a central source to large fuel and oxidant inlets covering adjacent sides of the fuel cell stack and sealed with properly designed gaskets. The exhaust gases are collected on the opposite sides with similar systems.

Note 2 to entry: Internal manifold design refers to a system of ducts inside the fuel cell stack and penetrating the bipolar plates that distributes the gas flows among the cells.