The Omnigrip 20-1/2" square has a diagonal line for triangle cuts; the ruler has extra 0.5in on two sides for seam allowance. In general, Omnigrip square rulers are 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. The 20-1/2" square ruler has the following standard Omnigrid / Omnigrip features:
Patented non-slip backing to hold ruler in place during cutting
Edge markings for accurate measuring
Laser cut edges for smooth, deep cutting
Patented double-sight lines that show up on light and dark fabrics
Diagonal line for triangle cuts
Heavy-duty durable acrylic material
Left- and right-hand numbering and angle system
 
OGN205