Janome Purple Tip Needles HA1SP-N 5PK - for sewing with stretch

They are specifically designed to effectively prevent skipped stitches when you are sewing with stretch fabrics; multiple layers of fabric eg quilts; and when sewing across bulky seams eg at a hemline.
 Yes, it has a ball point tip but also have a COBRA which opens up the fibers of the fabric allowing the needle to pierce thick layers, tightly woven fabrics or “difficult” stretch fabrics with ease.  The needle actually goes between the fibers.