Figure 2 : An artist’s rendition of borehole equipment.

From: Reconstructing a hydrogen-driven microbial metabolic network in Opalinus Clay rock

Figure 2

For better clarity, the polyvinyl chloride screen is not shown. Neoprene packer isolates the borehole water from the oxic atmosphere of the Underground Rock Laboratory galleries. Polyamide lines allow to sample borehole water, and to inject APW and H2 (which is creating a headspace) at different depths.