The FMS VNAV (Flight Management System, Vertical Navigation) panel give you control over the thrust (speed) component of your aircraft's FMS route.  The FMS VNAV panel also lets you adjust the cruising altitude of your FMS route.  With the "set MCP" box checked, changes to your FMS route will also be reflected in the relevant values displayed in the fields of your aircraft's MCP.  If this box is unchecked, the values in your FMS VNAV panel will not be consistent with those displayed in your MCP.  Consistent with the other Flight Deck Controls, the fields in the FMS VNAV panel use the same color scheme.  The  FMS VNAV panel also is the home of the Crossing Restriction Panel.

If you click on the "CRZ ALT" button, a drop-down menu will appear, listing available cruising altitudes, or flight levels.  When you select an flight level from the list, it will load into the FMS and will display in the CRZ ALT field of the FMS VNAV panel.  These values are to be used during the cruise phase of your flight.  You can use your keyboard to directly type in this field.

Note: Altitude values lower than those displayed in this list should not be used in the CRZ ALT field, since such low flight levels are typically associated with descent or climb phases of flight, not the cruise phase of flight.  As a reference, your current phase of flight is displayed on your aircraft's PFD.

By clicking on the "CLB SPD" button, a drop-down menu will appear, listing available climb speeds in knots.  When you select a speed from the list, it will load into the FMS and will display in the CLB SPD field of your aircraft's FMS VNAV panel.  These speeds are to be used during the climb phase of your flight.  You can use your keyboard to directly type in this field.

Clicking on the "CRZ SPD" button will display a list of available cruise speeds.  When you select a speed from the list, it will load into the FMS and will display in the CRZ SPD field of your aircraft's FMS VNAV panel.  These speeds are to be used during the cruise phase of your flight.  You can use your keyboard to directly type in this field.

The cruise speeds can be displayed in either mach numbers or knots.  If the radio button marked "Mach" is selected, the cruise speeds in both the drop-down menu and the CRZ SPD field will be displayed in mach numbers.  If this radio button is not selected, the speed values will be displayed in knots (see the two images below).  The Mach / knots setting of your aircraft's FMS VNAV panel also determines how the speed field in your aircraft's MCP are displayed.  Notice there is an identical "Mach"-labeled radio button located in the MCP.  These two buttons are permanently linked, so that they always match.

If you click on the "DES SPD" button, a drop-down menu will appear, listing the available descent speeds, in knots.  When you select a speed from the list, it will load in the FMS and will display in the DES SPD field of your aircraft's FMS VNAV panel.  These speeds are to be used during the descent phase of flight.  You can use your keyboard to directly type in this field.