These are really handy add-ons for the Grip-Tite Magnetic Feather Boards. The guides attach to the side of the Grip-Tite GT2000, and the abrasive roller is angled to steer the lumber toward the fence with about 10lbs of side pressure while the Grip-Tites are attached to the fence's vertical face using the Grip-Tite Steel Fence Plates.