TrueCut 12-1/2 by 12-1/2 inch Ruler. The ruler track on a TrueCut ruler interlocks with TrueCut Rotary Cutters (not included) to give you precise, straight cuts every time. The track prevents your cutter from slipping off the ruler"s edge. This ruler also features built-in holes along the entire ruler for marking your fabric. Measures 12-1/2 by 12-1/2 inches.