The Quick Curve Ruler© comes with a free pattern called "Urban Runner". The ruler is to be used with all Sew Kind of Wonderful© patterns. It is used to cut the curve shapes out and square the blocks up after piecing. The ruler is a quality acrylic ruler with a curve cut out, where your rotary blade of any size will fit into. It's 7" x 12" in size and has a hang hole for storage convenience.