Two needles in one shaft, this allows the user to use two different colored threads. It is great for top stitch accents.

Also great for hemming jersey fabrics. With a straight stitch on the machine, on the front side of the fabric you'll have two parallel stitches while on the back there is a zig zag stitch, so the seam will stretch with the fabric.

It can be used with any machine that sews a zig zag. Select the stitch, then hand turn the wheel at first gently, to make sure it can be sewn with a twin needle.