12 1/2 Inch x 12 1/2 Inch Omnigrid Ruler

The Omnigrid 12-1/2" x 12-1/2" ruler features an extra ½" width for seam allowances; it is used to cut, square and trim blocks sized 12-1/2" and under when quilting.  
In general, Omnigrid square rulers are used for secondary cutting of strips, and to square up finished quilt blocks Use with a rotary cutter or a straight-edge blade
The 12-1/2" x 12-1/2" ruler has the following standard Omnigrid features:
Diagonal angle line
Edge markings for accurate measuring
Laser cut edges for smooth, deep cutting
Patented double-sight lines that show up on light and dark fabrics
Heavy-duty durable acrylic material
Left- and right-hand numbering and angle system