Marine approved 25 ft³ (0.7 m³) of engine compartment volume. NFG models feature corrosion resistant non-refillable cylinders. Installation requirements 127mm wide x 323mm height. Automatic Discharge (Heat Actuated), Manual discharge option (requires bi-directional cable) Pressure Gauge, Pressure Switch (System Supervision and Discharge Indicator), Mounting Bracket (Vertical / Horizontal), Cylinder Status Indicator: 12VDC Light Bulb