KLASSE twin needles stitch two parallel lines in one pass for hems, pintucks, and decorative topstitching on twin-needle capable machines. This card includes one jeans/denim twin needle in size 100/16 with 4.0 mm (0.16 in) point-to-point spacing. Follow your machine manual for twin-needle threading, sew at a reduced speed, and test on scraps to confirm tension, needle clearance, and stitch width before starting.