How would you like to have a ruler and cutter that gave you straight cuts every time? No more slipping away from the ruler for crooked cuts! No more accidentally cutting into your ruler, or running over the top! The raised edge on every ruler is a patented "Ruler Track" that interlocks to the special "Cutter Guide" on the TrueCut rotary cutters. As you move the cutter along the ruler's track, the guide keeps the cutter from veering away from the ruler's edge.