Each of these tube-shaped cores can be removed for repair or replacement. Their technology uses the Proton Exchange Membrane type of fuel cell, their novel approach is the size they are able to create them at. Each microcell is around 500-1000 micrometers in diameter, and can be produced via an automated extrusion process.
Their site says that microcells are "a small step toward reducing global warming." They plan on scaling up their cells to 50kW plus for automotive purposes.