These milward universal twin machine needles are designed to allow you to sew perfectly parallel lines of stitching to create seams top stitching pin tucks or other embellishments its a simple way to create incredibly professional looking work with wonderful attention to detail the space between these needles is 3 mm and the needles themselves are the no 80 size when working with these twin needles its best to sew at a slower speed to ensure precision no 80 universal3 mm spacetwin n