Marine approved 750 ft³ (21.2 m³) of engine compartment volume. NMD models feature corrosion resistant refillable cylinders. Installation requirements 419.1mm wide x 779.78mm 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