This one has two toes with a slot in the middle between the toes.
It can sew on the left side
or on the right side
or straight stitch in between the toes.
And you don't have to change the foot to sew zippers, piping, or anything else you would use a zipper foot for - just loosen the thumbscrew in the back and slide the foot to the desired position. I can't believe that, with all my years of collecting sewing machines, I have never before seen a foot quite like this.
I have been using this foot on my Anker RZ for all the sewing I do on that machine except zig zag. The only foot I have is high shank and the only high shank machine I have out and set up for sewing is the Anker so it was a natural pairing.
Since I like the foot so much, I searched for a source so I could add them to the inventory of my Etsy shop. I have found them in high shank, low shank, and Singer slant shank.
Ed's Vintage Sewing Machine Shop