Gil nailed it on the head with what it monitors,
you don't want the alcohol leaking or worse yet the hydrogen leaking back inboard into a sealed tight hull. Right now the pic shows the Mk 25 monitor panel in "calibration" mode and that did exactly what it sounds like. it calibrated the surrounding air with what is supposed to be "within limits" set into it by the manufacture. Currently we have the monitor panels but we don't have the NAVOL Monitors that went into the weapons, I am trying to track down a monitor that was actually in the weapon for use by Torsk on loan or for permenant display (when the vols are onboard)