To Construct a Shell Solid with One or More Faces Removed

Select the Shell Solid tool.
In the Shell Thickness field, type the desired thickness value.
If necessary, turn on Shell Outward.
Select the solid.
The solid highlights. Simultaneously, the face nearest the screen pointer location highlights also.
Select the face to remove (with a data point).
The face highlights.
Do one of the following:

Accept, to create the shell solid.

or
Select further faces for removal (with <ctrl+data point>).
Accept, to create the shell solid.

Creating a shell solid | Left: Select the solid (1). | Center: Select the first face to remove with a data point (2) and the second face with a <Ctrl> data point (3). | Right: Accept (4), to create the shell solid.

Rendered view of the shell solid.