On the attachment the number 26532 Simanco is engraved, however the instructions (dated February 1930) and box have the number 26538 which shows a photo for same attachment. Every attachment that I have seen has the 2 different numbers so I assume that is just how it was made. I have included a sample of the amazing stitch this is capable of producing. From The Singer Featherweight Shop website. Truly, one of the most unique and ingenious attachment designs ever made by SINGER.
It makes a lovely curly-q stitch! As you can see in the photos above, this attachment does work on a Featherweight 221 or 222K, but will also fit the 15, 66, 99, 101, 115, 127, 128, 185, 192, 201, and 1200 as well as most other low shank Sewing Machines. The 222 machine arm has an ever so slight difference to the back of the arm under the presser bar lever (compared to the 221 model). Therefore, it takes a little bit more maneuvering into position to fit on the 222.With a little patience and maneuvering into the correct position, along with following the directions carefully, slowly and precisely, you will be able to add beautiful embellishments to your artistic sewing projects. Stamped designs or other figures can easily be followed with a very attractive ornamentation produced. We recommend using a spool of Sulky 12wt thread for use on the Spool Wire. It has a nice weight that is comparable to the original thread in the store sample. You'll notice in the photos above that a different color spool wire thread was used compared to the needle and bobbin thread. This adds a nice contrast.