2-3-4 Thread Stitch Capability – Stitch options for seams, seam finishes, hems and more. Differential Feed – Prevents seams in knits from stretching and lightweight fabrics from puckering. Rolled Hems and Narrow Hems – Four different fine hemming options for various looks. Adjustable Tensions – Keeps stitches balanced, yet adjustable for various serger sewing techniques. Adjustable Stitch Length – Set stitch length as desired for your thread and sewing technique..Adjustable Lower Knife - Determines cutting position so you can set stitch width as desired. Movable Upper Knife – Trims excess seam allowance as you sew; disengage to sew without trimming.. International products have separate terms, are sold from abroad and may differ from local products, including fit, age ratings, and language of product, labeling or instructions.