The Quick Curve Ruler© by Sew Kind of Wonderful is quality acrylic with a curved cut-out where your rotary blade, regular or jumbo, fits into. It measures 7 in. x 12 in. in size and has a hang hole for storage convenience. One ruler, multiple patterns, endless possibilities! The Quick Curve Ruler comes with a free pattern called "Urban Runner," ideal to familiarize yourself with using the no stress, no pinks process for sewing curves. It is the ruler necessary to use with One Wonderful Curve: 12 Contemporary Quilts and other Sew Kind of Wonderful patterns, to cut the curve shapes out and square the blocks up after piecing.