This sewing rulers is made of high-quality acrylic,0.3mm/0.12Inch thick enough, and not easy to break.laser-cut for a cleaner edge. Square quilting rulers are made from acrylic material and designed for quilting, sewing, measuring, drawing, and crafts. Providing a clear view of measurement on light or dark material. This quilting ruler set includes 4 square rulers,50 Pieces Non-slip Rings, quilting patchwork ruler set can meet all your patchwork needs,non-slip grip rings to prevent sliding as you cut. Acrylic clear ruler measure: 4.5x4.5Inch, 6x6Inch, 9.5x9.5Inch, 12.5x12.5Inch.2 sheets of grips, and each sheet has 25 pieces of large outer rings and 25 pieces small inner circles total 50 Pieces. These Non-Slip Grips to the back of any ruler to increase safety and cutting accuracy by preventing slipping.High quality material, Semi-Transparent, so your project visibility is not impaired.