This cap has six holes so that you can insert a platinized electrode and stainless steel electrode for in-situ electrolysis and lines for CO2 sparging, in addition to the inflow/outflow lines.
Important: only use high-temperature plastics if you plan to heat-sterilize this cap.
The author remixed this model.
This design add extra holes in different orientations to the Pioreactor vial cap, so that you can insert electrodes for in-situ electrolysis and lines for CO2 sparging, in addition to the inflow/outflow lines.