This open-source hardware features thicker flow field plates with stringent flatness and parallelism tolerances and uses o-seal fittings for the inlets and outlets. The rest of the design, for example the triple serpentine flow field pattern, is almost identical to existing ambient pressure LTE cells used at the National Renewable Energy Laboratory (NREL). Figure 1 shows an exploded view of all the components that make up the cell assembly. 3D CAD models and 2D technical drawings for the numbered parts (5900-00-01 – 5900-00-05) are included separately available for download.