The Omnigrip 2.5in x 18in ruler is ideal for cutting short strips and sashing; it has an extra 1/2in for seam allowances. Omnigrip rectangle rulers are used for cutting strips and trimming fabric edges during quilt making or when executing a variety of sewing and fabric craft projects. Use with a rotary cutter or a straight-edge blade. Patented non-slip backing to hold ruler in place during cutting; Heavy-duty durable acrylic material.