The Omnigrip 5.5in x 5.5in square ruler is used for secondary cutting of strips, and to square up finished quilt blocks. Use for quilting, sewing and crafts - or any DIY project that calls for cut fabric. Use with a rotary cutter or a straight-edge blade. Patented non-slip backing to hold ruler in place during cutting. Edge markings for accurate measuring and laser cut edges for smooth, deep cutting.