Through All is one of the extent options for protrusion and cutout features. The following examples show the effect of using Through All for cutouts.

The first figure shows a profile extruded through all, to one side.

The next figure shows the same profile extruded through all, to the other side.

The next figure shows the same profile extruded through all, to the both sides.

The next figure shows a similar case, except that the top of the profile has been left open. Notice that the ends of the profile are extended so that the feature cuts off the top faces of the part.