The first view presents the installed back pressure regulator, B P R 2, connected to an inlet and an outlet. Hydraulic oil flows through the horizontal line from the inlet, through B P R 2 and towards the outlet. A nitrogen, N 2, supply line connects to the regulator from above. The second view presents the cylindrical Equilibar back pressure regulator with multiple fasteners on its upper surface. A centimetre scale beside the regulator indicates its height.