The size 100/16 needle has a wing on each side of the shaft that causes the threads to separate when using some decorative stitches. Threads are moved/separated, not cut. Use with light or medium weight woven fabrics. Popular for heirloom sewing and to create decorative cutwork. Size 100/16 would be suitable for batiste, but less noticeable on quilting weight fabric that may need size 120/19.