When making a frame, opposite miters need to be cut into each end of the boards. With a regular gauge, set the angle at 45-degrees for the first cut. Then, readjust the gauge to set it for the second cut. This miter gauge has two faces at 90-degree angles to each other. Use one side to make the first cut, then move the board to the other face to make the second cut. There are no adjustments to be made and the angles are exact. The miter gauge has holes to attach a sacrificial fence to support bigger cuts.