Without a doubt the Swiss Automatic Zig-Zag Attachment is the best available zig zagger for Featherweights. It is recognized as the best zig zagger that Singer ever made. It is Swiss made and the most expensive zig zagger for a Featherweight. But, just like Featherweights, they are so darn cute and fairly difficult to find.
The Swiss Zig-Zag Attachment conveniently fits into the Featherweight carrying case.
It comes in an attractive cream colored Bakelite case with a small feed dog cover and an attaching thumbscrew.
The thumbscrew is often missing.
The Bakelite case, as cute as it is, is subject to having cracks.
The case measures 4"x2"x2.25".
These zig zaggers are beautifully made, easy to use and work well. They use cogs to get fancy zig zag stitches but without the cogs it does plain zig zag stitches with adjustable bight and stitch length. It can also do straight stitches.
The zigzagger has either five or ten cogs that can, when installed, give different zigzag stitches.
There are two models of this zigzagger but there is not much difference between the two. One model has five cams and one has ten and one has a steel shroud around the mechanism and the other has a cream colored Bakelite shroud (that matches the case) around the mechanism.
Model 160990 has the steel shroud with "Singer" and "Made in Switzerland" stamped onto it.
This model usually comes with five numbered cams but sometimes has ten as the cogs five cams numbered 6-10 could be purchased .
The manuals come in either English or German. English reproductions are available online. The instructions in the manuals for the two models are very similar.
Most people find model 160991 a bit more attractive because of the cream Bakelite shroud. However, the Bakelite is not as durable as the steel shroud and often there are cracks in the Bakelite. It can also pick up an "age" patina.
This model comes with ten cogs that come in a great little organization tray.
Despite what you may read elsewhere there are two different models of this zigzagger. The steel shrouded attachment is not a cream Bakelite attachment where the Bakelite has been removed. The steel shrouded attachment is a distinct attachment from the attachment with the Bakelite shroud. They have different model numbers, model 160990 and model 160991.
If you are lucky enough to own a 222K Featherweight you can sew with this zigzagger without using the feed dog cover as the feed dogs can be lowered out of the way.
BONUS
As a big bonus the Swiss Automatic Zig-Zag Attachment can act as a walking foot. Both models have feed dogs. The attachment could be called the Swiss Automatic Zig-Zag and Feed Dog Attachment.
An excellent and versatile, but expensive, attachment for a Featherweight but possibly the ultimate Featherweight attachment.