You can use a section box to focus your review on specific and limited areas of the model. The section box can be moved, rotated, and scaled with the sectioning gizmos, available from the Sectioning Tools tab 
Transform panel. You can also manipulate the section box numerically.
By default, when a section box is enabled, the move gizmo is used, unless you have already selected a different gizmo before activating the section box. All gizmos share the same location/rotation. This means that moving one gizmo affects the position of others.
When the section box is first created, the default size of the box is based upon the bounds of the current viewpoint. The box is created to fill the view such that no part of the box is drawn off-screen. Afterwards, enabling a section box restores the saved position, rotation, and scale information used if it is available for the current viewpoint.