Creative Grids 9" Seam Guide makes measuring perfect diagonals a breeze. This 0.5" x 9" drawing tool can be used to mark the diagonal of fabrics up to 9" and precut squares up to 6.5" and has a slotted center that can be marked through with any mechanical pencil. To create a cut line, simply mark dotted lines along the center slots or to create stitch lines, draw along the edges of the tool for marks at 0.25" on either side of the center of the square.
This notion is ideal for making half-square triangles and features Creative Grids' exclusive grip that holds fabric in place while measuring and drawing, eliminating slippage and inaccurate markings.