Level: Specifies the reference level of the pipe (3D, section, and elevations views only).
Diameter: Specifies the diameter of the pipe. If connections cannot be maintained, a warning message displays.
Middle Elevation: Specifies the vertical elevation of the pipe relative to the current level. You can enter a Middle Elevation value or select from a list of remembered Middle Elevation values.
/: Locks/unlocks the elevation for the segment. When locked, the elevation of the segment is maintained and connections cannot be made to segments at a different elevation.
Apply: Applies the current Options Bar settings. When you specify a Middle Elevation to draw vertical pipe in a plan view and click Apply, Revit creates the vertical piping between the original Middle Elevation and the setting being applied.