By default, the Cube Mode sets the Projector to generate a force field in the shape of a cube that is exactly 1 block thick.
Each Scale Module increases the size of the force field by 1 block in all directions.
Field adjustment
The Cube Mode item can also be used to create cuboid (or right rectangular prism) shape force fields. Placing a Scale Module into an item slot marked by a directional arrow will scale the field by 1 block in only that direction. For example, to increase the height of a force field by 1 block; add a Scale Module into an item slot marked by a directional arrow pointing towards the top-left or top-right of the GUI screen.