Diagonal Seam Tape
This magical tape is easy to apply to your sewing machine, and makes it so much faster to stitch up half-square triangles! It can also be used as a guide for stitching a perfect 1/4" seam allowance. The tape is easily removed without leaving a sticky residue, and one roll has 10 yards - which will last you years!
Watch the video to see how Diagonal Seam Tape works: