Marine approved 250 ft³ (7.1 m³) of engine compartment volume. NMD models feature corrosion resistant refillable cylinders. Installation requirements 203.2mm wide x 510.54mm 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