All TrueCut Rulers come with the TrueCut Ruler Track. This raised edge, combined with the guide on our cutters, is what makes it possible to achieve straight, precise cuts every time. The track and guide prevent your cutter from slipping off the ruler"s edge. These standard rectangle quilting rulers are great for just about every project, especially precise measurements and cutting strips. The Original 6"x24" and the new 6.5"x24.5" are great for cutting fabric off the bolt, and give that extra bit of reach for larger projects. The 6.5"x12.5" is perfect for smaller projects. Both the 6.5"x24.5" and the 6.5"x12.5" have built-in seam allowances on one side.