Marine approved 150 ft³ (4.2 m³) of engine compartment volume. NMG models feature corrosion resistant non-refillable cylinders. Installation requirements 145mm wide x 523mm height. Manual Only Discharge (Requires Bi-Directional Cable), Pressure Gauge, Pressure Switch (System Supervision and Discharge Indication), Mounting Bracket (Vertical / Horizontal), Cylinder Status Indicator: 12VDC Light Bulb