As well as for marking seam lines, You can use Tailor-tack foot #7 for sewing elegant embellishments, imitation hemstitch (fagoting), fringe, and 3D effects.
When sewing together two pieces of fabric with Tailor-tack foot #7, the thread tension is loosened slightly so that the thread can pass easily over the ridge in the centre of the foot. The zigzag stitch forms loose loops, slide off to the back thanks to the special V-shaped opening on foot.
For marking seam lines or darts, the fabric is carefully pulled apart after sewing. You can also use the Tailor-tack foot #7 for decorative purposes.